Thread about GPU-mining and Litecoin

[coblee]

The original purpose of Litecoin is to be a CPU coin where anybody with their computer can mine litecoins. What has happened with Bitcoin is that GPU mining on bitcoin was a lot more efficient, so a lot of people starting mining bitcoins with GPUs. This pumped up the difficulty and made CPU mining unprofitable and therefore pointless. I don't want this to happen to Litecoin and I think most people agree with me on this.

Recently, there has been some rumors that mtrlt has modified his GPU miner to work with Litecoin. And he claims to have been able to create a GPU miner that outperforms CPU miner by a lot. Of course, all this could be FUD thrown at Litecoin by Solidcoin supporters. But I have talked to mtrlt about this and he seems genuine. So I'd like to get to the bottom of this.

Here's what I'd like to accomplish:
1) Figure out if GPU mining litecoins is indeed more efficient. And if so how much better is it.
2) Do we want to switch to a new hashing algorithm that is more GPU-hostile.
3) If we do want to switch, there are a ton of other questions. Can we modify scrypt params or do we need something totally different. How far away do we do the algorithm switch? How do we get miners/pools/clients ready for the switch so that there's no downtime?

Everyone, please refrain from SolidCoin bashing in this thread. And SolidCoin supporters, please refrain from posting unless you have something constructive to say. Thanks.

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[Ahimoth]

If you want to believe me, then I can vouch for mtrlt's gpu miner being significantly more efficient than any current cpu miner for scrypt.

From what I know of the gpu miner, option 3 of modifying the scrypt parameter will have minimal impact. The pad size did not seem to matter much, and can be compressed for lack of a better word, with on the fly value reconstruction. So any increase in pad size will have a relatively equal impact on cpu miners until you exceed their cache size, at which point, gpus may become even more efficient.

I think you will be stuck with option 2, finding a completely different hashing algorithm.

[Ahimoth]

Not in an attempt to troll the thread, but if you look at solidcoin's hash code, you will see it has random reads and writes that are of varying size, spread out over a large memory range, and are randomly aligned. These are key techniques in creating havoc with a gpu's memory access methods. I would suggest looking for code that has similar traits if you really want to defeat gpu's or at least keep them on a level playing field with cpus.

[DeLorean]

I can't really contribute to ideas that would make Litecoin more GPU-unfriendly... but I do agree that it is essential to Litecoin to be CPU-friendly and CPU-unfriendly. If this turns out to be true, something needs to be done to remedy it or Litecoin has no valid purpose.

[ssvb]

1) Figure out if GPU mining litecoins is indeed more efficient. And if so how much better is it.

I guess the only option is to just implement GPU miner and check how fast it runs. It is really surprising that so few people have actually tried this so far.

3) If we do want to switch, there are a ton of other questions. Can we modify scrypt params or do we need something totally different.

Maybe scrypt author can be contacted and asked about his opinion?

How far away do we do the algorithm switch? How do we get miners/pools/clients ready for the switch so that there's no downtime?

This is actually interesting. If I understand it correctly, bitcoin itself does not rule out a possible change of hashing algorithm in the future (if the need arises). Attempting this for litecoin now could be treated as some kind of rehearsal and provide a valuable experience.

[someguy123]

Wouldn't changing the algorithm force a new blockchain for litecoin? That'd screw up every pool, exchange, client, etc. which is probably going to annoy a lot of the network.
And if that did cause some sort-of "litecoin 2", that would send the value of litecoin downhill, meaning anyone who currently has a lot of their money in litecoins, ends up with nothing...

Another thing is that mtrlt still refuses to show any proof... You can't really say much when he could just be spreading FUD. At most the only proof I see is his 3MH/s on squidnet, but that doesn't show his stale rate to tell whether it's all just bullshit "fake" work, and plus I know of a few people who have managed to get similar hashrates by mining on their businesses clusters, or home clusters, which surprisingly a lot of people do.

[Ahimoth]

Since I was asked to clarify, "significantly more efficient", I guess I will post some hash per watt numbers.

According to litecoin wiki mining hardware comparison, an AMD Phenom X4 955 at 3.6ghz gets 24kh @ 125 watts. This translates to 0.192kh per watt.
A gpu rig consisting of 69xx series gpus can produce 998kh @ 920 watts at the wall. This translates to 1.08kh per watt.

So does at least a 5.6 factor increase in *efficiency* qualify as "significantly more"?

Consider the litecoin wiki entry for the Intel Core i7 860 which produces 25kh at 153 watts (a believable wattage consumption for the entire system). It gives a system kh/watt score of only 0.163. The gpu example is now a factor of 6.6 times more efficient.

PS, Mtrlt has gotten better kh/watt scores by playing with the clocks and voltages, but I figured I would give you an initial test result.

[CoinHunter]

Wouldn't changing the algorithm force a new blockchain for litecoin? That'd screw up every pool, exchange, client, etc. which is probably going to annoy a lot of the network.
And if that did cause some sort-of "litecoin 2", that would send the value of litecoin downhill, meaning anyone who currently has a lot of their money in litecoins, ends up with nothing...

Coblee has multiple options.

1) Drop support for litecoin1 and start litecoin2 or whatever, and give people all the existing coins in Litecoin1 into Litecoin2 (I did this with SolidCoin v2). Of course this also means the guys GPU mining still have their new coins in the new network but it potentially means you can start fresh with a new algorithm. It's a lot of work however.

2) Do a forking change in litecoin itself. The problem with this is the "old network" will continue in parallel with the "new litecoin". Which leads to a lot of support issues "Which litecoin are you on?".

3) Start an entirely new coin. Like he did with Litecoin over fairbrix. Probably the second easiest option to pull off since you don't have to support multiple old things and allows him to do some things from scratch a bit better. However the downside is the original Litecoins probably decrease in value due to no more developer (like tenebrix and fairbrix).

4) Do nothing. The easiest option.

The hardest thing is, unless you are well versed in understanding CPU and GPU architecture making a CPU hard coin is very difficult. Given Coblees failure to know if Scrypt was GPU hard are we going to believe he can now make one that is? This will require a lot of work and a lot of testing to verify. And you're going to need talented C++ and OpenCL coders to help you out I think.

[shawnp0wers]

If the efficiency is 5-6 times that of a CPU, it's still a far cry from Bitcoin's CPU-worthlessness. It would be interesting to see the math concerning how worthwhile it would be to mine BTC vs LTC on a theoretical GPU scrypt miner.

Perhaps the ability to mine LTC with a GPU will still be moot. If it's more economical to mine for BTC and buy LTC with the profits, it would be foolish to mine LTC with a GPU even if possible.

Anyone like crunching numbers? What would the price of LTC need to be in order to make GPU mining worthwhile? I don't think we're there, but like I said, I haven't run the numbers at all.

[someguy123]

If the efficiency is 5-6 times that of a CPU, it's still a far cry from Bitcoin's CPU-worthlessness. It would be interesting to see the math concerning how worthwhile it would be to mine BTC vs LTC on a theoretical GPU scrypt miner.

Perhaps the ability to mine LTC with a GPU will still be moot. If it's more economical to mine for BTC and buy LTC with the profits, it would be foolish to mine LTC with a GPU even if possible.

Anyone like crunching numbers? What would the price of LTC need to be in order to make GPU mining worthwhile? I don't think we're there, but like I said, I haven't run the numbers at all.

Well,

[04:12:10] <@PooL-X> The expected generation output, at 200 KHps, given current difficulty of 1.5926655, is 126.31 LTC per day, 5.26 LTC per hour, Estimated time to find a block is 9 hours 30 minutes 3 seconds

That's the amount of kh/s mtrlt was saying, or at least an average: that's $1.20 a day.
Now, with my 6870 I get 300mh/s on bitcoin...which earns me an avg of 0.2BTC a day, which is around $1/day
So really they're about equal, if bitcoin price rises any more, it's more worthwhile to mine bitcoins on a GPU.

A gpu rig consisting of 69xx series gpus can produce 998kh @ 920 watts at the wall

Okay that's

[04:15:36] <@PooL-X> The expected generation output, at 998 KHps, given current difficulty of 1.5926655, is 630.27 LTC per day, 26.26 LTC per hour, Estimated time to find a block is 1 hour 54 minutes 15 seconds

630 LTC a day, thats around $6.30 a day, no idea how much they'd get with bitcoin, probably a LOT more $ value in GPU mining on bitcoin with them...

[gmaxwell]

assisting in a reduction of simultaneous block finds.

Having two different algorithms doesn't reduce simultaneous block finds, only making blocks further apart does.  

Anyone like crunching numbers? What would the price of LTC need to be in order to make GPU mining worthwhile? I don't think we're there, but like I said, I haven't run the numbers at all.

Why does it matter?  For may (most? almost all who aren't stealing power/computing?) people it's long been more efficient relative to power costs to mine bitcoin with gpus and sell for litecoin if you really want litecoin.   I can't see how this would make it any _worse_ than that.  Perhaps efficient GPU mining will take litecoin back from the thieves and make it profitable for honest people to mine again?

You can't really say much when he could just be spreading FUD.

So, how much have you placed against this at http://betsofbitco.in/item?id=292  ?   I'd think anyone sure enough to call someone a liar would be willing to put up way more than 1.50 BTC.

[shawnp0wers]

Interesting. It's a shame it so close, it would be nice to have a *little* wiggle room.  That said, price parity based on GPU speeds would be a legitimate way to stabilize LTC prices. I just wish it wouldn't stablize the price so low, lol!

[shawnp0wers]

Why does it matter?

The advantage isn't for folks willing to invest hardware, the advantage with CPU mining is that people can mine without any initial investment. I totally understand what you're saying, and maybe the "accessible to the masses" isn't even a practical idea -- but that's the idea. Anyone can mine with what they have.

[Ahimoth]

Anyone like crunching numbers? What would the price of LTC need to be in order to make GPU mining worthwhile? I don't think we're there, but like I said, I haven't run the numbers at all.

easy.. the same rig on bitcoin would make $5.17 daily, whereas on litecoin it would make $6.11 daily. This is according to allchains.info.

[DeathAndTaxes]

assisting in a reduction of simultaneous block finds.

Having two different algorithms doesn't reduce simultaneous block finds, only making blocks further apart does. 

I think you misunderstand what I was getting at ... it reduces the chance that a single source can find 2 blocks in a row ... makes the 51% issue maybe a 75% or more issue or whatever the stats would be.

You misunderstand 51% attack (like many other things).  With 51% (technically 50% + 1 hash per second) you will eventually have the longest chain., that is a mathematical certainty. 

Instead of attacker buying x CPUs or y GPUs he will now simply buy 1/2x CPUs and 1/2y GPUs.

[DeathAndTaxes]

You just proved what I was stating as the benefit, the attacker has to compete with BOTH sources .. either by "51%" both sources or having immensely more power on 1 source.. enough more hash power to compete with the more efficient miners.  And i called it a defense, not a prevention of that attack vector, meaning it just makes it harder.

Fail again.  

The network won't be twice as strong.  It will have half the hashing power in CPU and half in GPU.  The cost to attacker hasn't risen.

Buying X CPU.
vs
Buying Y GPU.
vs
Buying 1/2 X CPU AND 1/2Y GPU.

The strength of the network is split between both components.   At any given economic value the network will reach equilibirum between price and difficulty. By having different block types the combined difficulty for both blocks (2 blocks total) will be no higher than 2x a single block now.

Lots of extra code for no benefit.  It will not be any harder for an attacker to get 2, 6, 20, 100,000 blocks ahead of the honest chain using 2 types of blocks or 50.

TL/DR:
You:  If difficulty doubles then the network is stronger.  See you proved my point.
Me:
You:  See 1 + 1 is obviously harder than 2.
Me:

Maybe you suggest an idea he/LTC community could consider doing?

Nothing.  There is no proof this magical miner exists.  Changing hashing algorithm is a massive change and certainly non-trivial.  If/when independently the efficiency of GPU mining is verified the solution will depend on how high that efficiency is AND how various methods degrade that.

Doing something based on no proof is exactly what you want to happen.


If you would like to continue trolling my simple idea that coblee could choose to run with or not, fine but please stick to the OP and be planning what should be done for the benefit of LTC... is this not a more productive plan?  Maybe you suggest an idea he/LTC community could consider doing?
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[DeathAndTaxes]

Is there some reason you want just a single difficulty?  That would not make a lot of sense, you would need a difficulty per block type, otherwise having too much hashing from one source makes it impossible to mine efficiently on the other.

LOLZ.  Are you that dense.

I just used 1 + 1 = 2x as an example.  The split doesn't matter and obviously each block would have indepedent difficulty.

Let me make it simple.

THE ENTIRE LITECOIN NETWORK GENERATES X USD PER UNIT OF TIME.

X buys so much computee things (bleep, bleep boop boop -> hashs come out).   

Difficulty is a manifestation of X.  If X rises so will difficulty.  If X falls so will difficulty.  There may be fluctuations but equilibrium will be reached between difficulty and price.

Thus the COMBINED difficulty will always be a reflection on X.  Changing the number and types of blocks won't change anything.

Combined difficulty will always be a reflection on X.  Thus the cost to build enough hashing power will be a reflection on difficulty which is a reflection on X.

Only way the network gets stronger is if price goes up.  Period.  Moore's law doesn't help (it also helps attackers).  New tech breakthroughs (like GPU mining at higher efficiency) doesn't help because attacker can use it too.   Lower energy costs globally (say cold fusion) doesn't help because ... yup it helps attacker too.

The only thing that makes the network stronger is the revenue paid to miners in the form of fees/subsidies.  Since miners costs are in fiat what ultimately matters is the amount of fiat generated per day.

[coblee]

Viper's solution is not without merit. It would make it harder to 51% a coin in the earpy stages because you'd need both a bitcoin farm and a botnet.

[DeathAndTaxes]

Viper's solution is not without merit. It would make it harder to 51% a coin in the earpy stages because you'd need both a bitcoin farm and a botnet.

There are easier methods to protect a coin in the early stages than saddling it with a dual block structure long after it is no longer needed. 

[ThiagoCMC]

Don't give up of Litecoin!!
Everybody wants to see for sure that GPU-mining for Litecoins is a reality and efficient...

[iddo]

Here's what I'd like to accomplish:
1) Figure out if GPU mining litecoins is indeed more efficient. And if so how much better is it.
2) Do we want to switch to a new hashing algorithm that is more GPU-hostile.
3) If we do want to switch, there are a ton of other questions. Can we modify scrypt params or do we need something totally different. How far away do we do the algorithm switch? How do we get miners/pools/clients ready for the switch so that there's no downtime?

1)
If I understand the rumors correctly, a single high-end GPU would be about 25x faster than a single CPU core, as opposed to 5x faster that was initially predicted by ArtForz? Still a lot less than the 400x speedup of bitcoin with 5870 GPU vs single CPU core?

2)
I suppose that increasing the memory size parameter of scrypt to a very large amount (megabytes...) which doesn't fit in the cache would mean that it'd be infeasible to do hash attempts in parallel with a GPU (and maybe even with several CPU cores), but it also most likely means that people couldn't use their computer to do other stuff while mining litecoins due to system responsiveness issues. Therefore it's possible that the current scrypt parameters as chosen by ArtForz and Lolcust are the best, espeically if bitcoin GPU mining remains more profitable than litecoin GPU mining.


3)
Switching to another hashing algorithm in this case is relatively simple, just need a protocol change that says that starting from block #x in the future the PoW will be checked according to the new hashing algorithm. By contrast, if it was the case that there's full pre-image attack on scrypt (which ain't gonna happen while there's no pre-image attack on sha256) then there would also be a need to add a new data field that contains the new hash to all the old blocks in the chain, otherwise an attacker could use the pre-image attack replace an old block with his own malicious block (see https://bitcointalk.org/index.php?topic=191.msg1585#msg1585).
There would be no "downtime", you can let the miners vote (similarly to bitcoin p2sh vote, see https://github.com/bitcoin/bitcoin/pull/804) and see if they agreed to the switch before block #x is reached, and if there's no majority then the minority should withdraw their support before block #x so that this proposal would be cancelled in a smooth way. From the point of view of the fork being beneficial as a rehearsal to a similar bitcoin fork that could be useful in the future, I think that if the litecoin p2pool has relatively high computing power then it'd be interesting.

[ssvb]

If you want to believe me, then I can vouch for mtrlt's gpu miner being significantly more efficient than any current cpu miner for scrypt.

From what I know of the gpu miner, option 3 of modifying the scrypt parameter will have minimal impact. The pad size did not seem to matter much, and can be compressed for lack of a better word, with on the fly value reconstruction. So any increase in pad size will have a relatively equal impact on cpu miners until you exceed their cache size, at which point, gpus may become even more efficient.

Right now salsa20/8 is used as a core part of of scrypt (8 rounds for the inner loop). Replacing it with something like salsa20/2 (just two rounds in the inner loop) would significantly improve performance on CPU, because 4x less calculations would be involved. And the memory access pattern would remain the same, resulting in almost no improvement for the miners which depend on memory performance (GPU miners and also to some extent Cell/BE miner). So what's the problem? The variants of salsa20 with lower number of rounds are supposedly significantly less secure, at least in some cases:
http://fse2008.epfl.ch/docs/papers/day_3_sess_3/29_Lausanne_FSE08_camera_ready.pdf
http://www.ecrypt.eu.org/stream/papersdir/2007/010.pdf

But I don't know how exactly this all applies to scrypt, because cryptography is definitely not my forte. That's why I think that bringing up the issue to the scrypt author can make some sense. That is after we get a better idea of realistic GPU performance.

I think you will be stuck with option 2, finding a completely different hashing algorithm.
Not in an attempt to troll the thread, but if you look at solidcoin's hash code, you will see it has random reads and writes that are of varying size, spread out over a large memory range, and are randomly aligned. These are key techniques in creating havoc with a gpu's memory access methods. I would suggest looking for code that has similar traits if you really want to defeat gpu's or at least keep them on a level playing field with cpus.

This is all nice. But can we be sure that these convoluted hash calculations can't be algorithmically optimized and reduced to something that can run orders of magnitude faster?

[Schwede65]

According to litecoin wiki mining hardware comparison, an AMD Phenom X4 955 at 3.6ghz gets 24kh @ 125 watts. This translates to 0.192kh per watt.
A gpu rig consisting of 69xx series gpus can produce 998kh @ 920 watts at the wall. This translates to 1.08kh per watt.

So does at least a 5.6 factor increase in *efficiency* qualify as "significantly more"?

Consider the litecoin wiki entry for the Intel Core i7 860 which produces 25kh at 153 watts (a believable wattage consumption for the entire system). It gives a system kh/watt score of only 0.163. The gpu example is now a factor of 6.6 times more efficient.

to have a fair comparison:

it's measured at my btc-mining-rigs, the point is, that i only count the extra-cpu-watt of the rigs, because they are mining btc and a cpu-coin is mined extra, when there is one, when there is no coin to mine i save the watt

core i3 / 2.4 ghz / 3 threads / ~  8 w only for this / 10 kh/s =>1.25 kh/w
CPU / GPU // CPU is 1.157 more efficient

core i3 / 3.1 ghz / 3 threads / ~ 15 w only for this / 12.5 kh/s =>0.83 kh/w
CPU / GPU // CPU is 0.768 less efficient

core i7 / 3.6 ghz / 7 threads / ~ 46 w only for this / 32 kh/s =>0.695 kh/w
CPU / GPU // CPU is 0.644 less efficient

for me i can't see the 5- or 6-higher-efficiency-factor of the gpu...

[shakti]

Well, my theorethical researches give some unswers to Problematic.
Is Gpu-miner possible - YES, depends on implementation it can be made somehow better as CPU miner.
The performance of GPU miner is caped by Memory bandwith (you can't store all the data in Local/Shared memory of Device and have to use global Memory.
Global memory has havy latencies to access but managing an implementation where you will "hide" latencies by calculating in this time can work. You'll  still have cap in bandwidth ... the Fastest Bandwidth we have on common GPUs (as far as i know reading http://www.geforce.com/Hardware/GPUs/geforce-gtx-590/specifications used Nvidia GPU cause they have better bandwidth as AMD) is 327.7 GB/s. Sure it's best possible performance for just sequent read/write it's impossible to reach this in Scrypt calculation on GPU but we can calculate a Cap. One hash needs 128k writes and 128k reads to and from Global device memory. this means we can't calculate more hashes as

327.7 * 10^9 / 2 / 128 * 10^3 = 1.28 * 10^6 hashes.

this means the cap of performance is 1.28 MH/s.

The real implementation would be worser by factor 2 or 3 ...

Is this a problem ... well could be, but i don't think so.

[DeathAndTaxes]

One thing (somewhat theoretical) I would throw out there is that as GPUs become more "CPU like" they will devote the necessary resources (transistors and chip yield) to increased L1 cache.  GPU long since outstripped the growth in pixel counts so they devoted more resources to improved image quality at a fixed number of pixels and/or polygons.  The GPU resources are growing faster than developers ability to use them as devising more complex and realistic "effects" requires more human capital than simply doubling the polygon count or going from a 800x600 pixel count to 1920x1200 pixel count.  So it will be increases in GPGPU workload which increasingly drives development of future GPUs.   

GPU traditionally had very little local cache because there is no need when performing traditional graphics work.  That dynamic likely won't hold true in the future.  NVidia Tesla cards for example can be configured to double the amount of L1 cache because it is so useful in boosting performance of some GPGPU functionality.   Larger L1 caches will eventually trickle down into consumer grade products to.

No coin today is "anti-GPU" it is they can be described as "large L1 cache dependent".   Even if GPU mining is impossible w/ todays hardware the desire for GPGPU performance will drive higher cache in the SP for future GPU and eventually they will be able to perform with no limitation.

One "hard" alternative is to make the lookup tables so large they can only fit in main memory (say a 3.2GB lookup table).   That obviously makes the code less functional on those with limited system resources but given CPU access to memory is always lower latency that GPUs it becomes hard to defeat.  Eventually GPUs shared memory will be 4GB, 8GB, 16GB etc so possibly some algorithm which adjusts size of lookup table based on Moore's law might be needed (i.e. uses a 3.2GB lookup table at current block but that increases by 7% every 40,000 blocks as part of the protocol, maybe on a multiple of difficulty like every 8th difficulty adjustment is also a memory adjustment).

[shakti]

One thing (somewhat theoretical) I would throw out there is that as GPUs become more "CPU like" they will devote the necessary resources (transistors and chip yield) to increased L1 cache.  GPU long since outstripped the growth in pixel counts so they devoted more resources to improved image quality at a fixed number of pixels and/or polygons.  The GPU resources are growing faster than developers ability to use them as devising more complex and realistic "effects" requires more human capital than simply doubling the polygon count or going from a 800x600 pixel count to 1920x1200 pixel count.  So it will be increases in GPGPU workload which increasingly drives development of future GPUs.   

GPU traditionally had very little local cache because there is no need when performing traditional graphics work.  That dynamic likely won't hold true in the future.  NVidia Tesla cards for example can be configured to double the amount of L1 cache because it is so useful in boosting performance of some GPGPU functionality.   Larger L1 caches will eventually trickle down into consumer grade products to.

No coin today is "anti-GPU" it is they can be described as "large L1 cache dependent".   Even if GPU mining is impossible w/ todays hardware the desire for GPGPU performance will drive higher cache in the SP for future GPU and eventually they will be able to perform with no limitation.

One "hard" alternative is to make the lookup tables so large they can only fit in main memory (say a 3.2GB lookup table).   That obviously makes the code less functional on those with limited system resources but given CPU access to memory is always lower latency that GPUs it becomes hard to defeat.  Eventually GPUs shared memory will be 4GB, 8GB, 16GB etc so possibly some algorithm which adjusts size of lookup table based on Moore's law might be needed (i.e. uses a 3.2GB lookup table at current block but that increases by 7% every 40,000 blocks as part of the protocol, maybe on a multiple of difficulty like every 8th difficulty adjustment is also a memory adjustment).

Sure with new hardware situation will be other. Quantum computers are possible aswell and will be "common" someday aswell and it will change everything we know about Cryptography

[DeathAndTaxes]

Sure with new hardware situation will be other. Quantum computers are possible aswell and will be "common" someday aswell and it will change everything we know about Cryptography

True but the probability of GPU reaching L1 cache parity is much higher in the short term.  I would expect it within 1 generation (8000 series) but if not there it will certainly be there in the next-next generation.

So realistically you are talking about a 2-3 window before GPU have cache parity with CPU.  Using an algorithm which relies on that inequality is "futile" over even the short term.

Honestly I don't see the value in trying to limit hardware.  At this point GPU mining (which we don't even know exists) is still more valuable on Bitcoin.  So if someone was convinced Litecoin will take over the world it would still be cheaper to mine BTC and use that to buy LTC.  If miner i just interested in fiat profits well all that matters is which coin generates higher return on a given piece of hardware (or even more abstract a given amount of capital).

[Bitinvestor]

I agree with DeathAndTaxes on this one. It's not worth trying to limit hardware because it's improving all the time. By the end of this year Intel is expected to release their new Knights Corner 50-core CPU. That will be a good one for mining Litecoins, according to Artforz on btc-e. Are you going to try and stifle that one too?

Do you have any hopes of Litecoin ever becoming mainstream? It won't happen while 50% of the mining is done by botnets! That's why the Litecoin price is so low: nobody is going to put any serious money into a botnet currency.

A GPU miner is the best thing that could happen to LTC because botnets don't have GPUs. Let's leave Litecoin as it is and let's get mtrlt to release an open source version of his miner. I read that he spent only a few hours working on it so the Litecoin community should be able to buy it from him. I'm willing to donate 10 BTC towards this goal.

[CoinHunter]

I agree with DeathAndTaxes on this one. It's not worth trying to limit hardware because it's improving all the time. By the end of this year Intel is expected to release their new Knights Corner 50-core CPU. That will be a good one for mining Litecoins, according to Artforz on btc-e. Are you going to try and stifle that one too?

Do you have any hopes of Litecoin ever becoming mainstream? It won't happen while 50% of the mining is done by botnets! That's why the Litecoin price is so low: nobody is going to put any serious money into a botnet currency.

A GPU miner is the best thing that could happen to LTC because botnets don't have GPUs. Let's leave Litecoin as it is and let's get mtrlt to release an open source version of his miner. I read that he spent only a few hours working on it so the Litecoin community should be able to buy it from him. I'm willing to donate 10 BTC towards this goal.

I think you should find out more about why Coblee created litecoin :-

https://github.com/coblee/litecoin/wiki/Comparison-between-Bitcoin-and-Litecoin

For proof of work, Bitcoin uses the highly parallelizable SHA256 hash function, and therefore Bitcoin mining is a GPU-friendly task. Litecoin uses scrypt instead of SHA256 for proof of work. The scrypt hash function uses SHA256 as a subroutine, but it also depends on fast access to large amounts of memory rather than depending just on fast arithmetic operations, so it is hard to run many instances of scrypt in parallel by using the ALUs of a modern graphics card. This means that currently CPU mining is more efficient than GPU mining for Litecoin. In the future, GPUs or other dedicated hardware might prove useful for Litecoin mining, though the improvement over CPUs is likely to be less significant than it was for Bitcoin mining (e.g. 4x speedup instead of 400x speedup).

If your computer already mines bitcoins, then the CPU on that computer is probably idle, so you can simultaneously mine litecoins without affecting the speed in which your GPU mines bitcoins.

Either litecoin is a CPU coin or the major reason for its existence just disappeared?

From the latest stats it appears GPU mining scrypt is 25-35x faster than CPU, is able to be stacked in the same PC and is 6-10x more efficient.

Check out SolidCoins mining page for info on how a correct implementation of CPU/GPU hard algorithm should figure in performance.
http://wiki.solidcoin.info/wiki/Mining_Hardware_Performance

[DeathAndTaxes]

I believe this is do to the accessibility goals of LTC, true hardware will increase so algo changes only *need* to be made to keep the *common man* readily accessible to mining.  Right now if GPU mining proves good enough the common man becomes ostracized from this coin again and thus should warrant an algorithm adjustment... 5 years or whenever down the line that it takes for the common man to have the hardware you are talking about as generally available then it would be ok to let the algo slip into that new territory without an update, right now it seems just too soon ... imho at least.

Well the common man isn't mining it and likely will never mine ANY coin.  Mining isn't necessary for usage.  Mining like any commodity business will be limited to those with highest efficiency.  Lots of people buy/sell/trade gold a much smaller number of people actually mine it.

Still even if one believes CPU = greater adoption (and ignores the issue of botnets) just having a GPU miner doens't mean someone will use it.  If one can get x mining LTC and get 2x mining BTC on the same hardware well it doesn't really matter does it?

LTC GPU performance isn't just competing against LTC CPU performance but also BTC GPU performance as well.  You can mine ShortBusCoins with GPUs and have been able to for some time but hashing power is a tiny fraction (even adjusting for relative difficulty) of Bitcoin meaning most miners with the ability to mine ShortBusCoins simply chose not to.

Unless it is more profitable to mine LTC instead of BTC on a given piece of hardware it would be illogical make the switch.  Everything is fungible.

I can get LTC a variety of ways:
$$$$ -> LTC
$$$$ -> CPUs -> LTC
$$$$ -> GPUs -> BTC -> LTC
$$$$ -> GPUs -> LTC (unproven)

[dishwara]

Anyone can explain me why i am getting this error?

2012-02-17 22:01:10 Error 6 getting work. See http://curl.haxx.se/libcurl/c/libc
url-errors.html for error code explanations.
2012-02-17 22:01:10 Couldn't connect to server. Trying again in a few seconds...

I tried website mentioned, but cant find.
I used reaper 12 from http://wiki.solidcoin.info/wiki/Reaper

[DeathAndTaxes]

Anyone can explain me why i am getting this error?

2012-02-17 22:01:10 Error 6 getting work. See http://curl.haxx.se/libcurl/c/libc
url-errors.html for error code explanations.
2012-02-17 22:01:10 Couldn't connect to server. Trying again in a few seconds...

I tried website mentioned, but cant find.
I used reaper 12 from http://wiki.solidcoin.info/wiki/Reaper

Because it doesn't support litecoin?

[michaelmclees]

In my opinion, so long as a CPU rig can earn coins at a significant percentage rate of a GPU rig, then Litecoin is serving its purpose.  You have to keep in mind that a $1,000 CPU mining Bitcoin is going to take 60 years to find a block, while a $1,000 GPU rig will take about 2 months.  The CPU rig is .2% as efficient as the GPU rig.

Let's make the same comparison to LTC.  A $1,000 CPU rigs will make 30LTC a day while a $1,000 GPU rig will, according to rumor, make 600LTC per day.  The CPU rig is 5% as efficient.  There is a difference of 25 times between the inefficiencies of CPU's to GPU's regarding Bitcoin and Litecoin.

Even in a world of GPU miners, with Litecoin, the CPU is still very effective, especially when there is no initial outlay of money for the rig itself.  With Bitcoin, no matter how good your CPU is, it is utterly worthless for mining; this isn't even close to the case for Litecoin, if the rumors of GPU miners turn out to be true.

I see no reason for any changes.

[Mousepotato]

[04:12:10] <@PooL-X> The expected generation output, at 200 KHps, given current difficulty of 1.5926655, is 126.31 LTC per day, 5.26 LTC per hour, Estimated time to find a block is 9 hours 30 minutes 3 seconds

That's the amount of kh/s mtrlt was saying, or at least an average: that's $1.20 a day.
Now, with my 6870 I get 300mh/s on bitcoin...which earns me an avg of 0.2BTC a day, which is around $1/day
So really they're about equal, if bitcoin price rises any more, it's more worthwhile to mine bitcoins on a GPU.

I believe that quoted 200 KH/s is from a single 6990.  So 126.31 LTC per day from a 6990 equals roughly 0.2808 BTC per day.  You could just as well mine BTC to the tune of around .60XX BTC per day with the same card.  Unless I mis-read where that 200 KH/s came from, you'd really have to squeeze 400 KH/s+ out of a single 6990 before it even begins to become equal to net daily output from mining BTC.

[shakti]

I agree with DeathAndTaxes on this one. It's not worth trying to limit hardware because it's improving all the time. By the end of this year Intel is expected to release their new Knights Corner 50-core CPU. That will be a good one for mining Litecoins, according to Artforz on btc-e. Are you going to try and stifle that one too?

Do you have any hopes of Litecoin ever becoming mainstream? It won't happen while 50% of the mining is done by botnets! That's why the Litecoin price is so low: nobody is going to put any serious money into a botnet currency.

A GPU miner is the best thing that could happen to LTC because botnets don't have GPUs. Let's leave Litecoin as it is and let's get mtrlt to release an open source version of his miner. I read that he spent only a few hours working on it so the Litecoin community should be able to buy it from him. I'm willing to donate 10 BTC towards this goal.

I think you should find out more about why Coblee created litecoin :-

https://github.com/coblee/litecoin/wiki/Comparison-between-Bitcoin-and-Litecoin

For proof of work, Bitcoin uses the highly parallelizable SHA256 hash function, and therefore Bitcoin mining is a GPU-friendly task. Litecoin uses scrypt instead of SHA256 for proof of work. The scrypt hash function uses SHA256 as a subroutine, but it also depends on fast access to large amounts of memory rather than depending just on fast arithmetic operations, so it is hard to run many instances of scrypt in parallel by using the ALUs of a modern graphics card. This means that currently CPU mining is more efficient than GPU mining for Litecoin. In the future, GPUs or other dedicated hardware might prove useful for Litecoin mining, though the improvement over CPUs is likely to be less significant than it was for Bitcoin mining (e.g. 4x speedup instead of 400x speedup).

If your computer already mines bitcoins, then the CPU on that computer is probably idle, so you can simultaneously mine litecoins without affecting the speed in which your GPU mines bitcoins.

Either litecoin is a CPU coin or the major reason for its existence just disappeared?

From the latest stats it appears GPU mining scrypt is 25-35x faster than CPU, is able to be stacked in the same PC and is 6-10x more efficient.

Check out SolidCoins mining page for info on how a correct implementation of CPU/GPU hard algorithm should figure in performance.
http://wiki.solidcoin.info/wiki/Mining_Hardware_Performance

I see nothing correct in your Hashing Algorithm, i've implemented 2.5 faster Version of miner for it (CPU) and due lack of time and profit for mining there is even 3x-8x better implementation of GPU miner for Solidcoin so it's nothing other

[gmaxwell]

In my opinion, so long as a CPU rig can earn coins at a significant percentage rate of a GPU rig, then Litecoin is serving its purpose.  You have to keep in mind that a $1,000 CPU mining Bitcoin is going to take 60 years to find a block, while a $1,000 GPU rig will take about 2 months.  The CPU rig is .2% as efficient as the GPU rig.

Lots of gibberish on this thread.    A typical current generation quad core cpu will produce 18MH/s a similarly priced (and higher power consumption) GPU will produce perhaps 320 MH/s.    ~20x is nowhere near 500x.

[michaelmclees]

In my opinion, so long as a CPU rig can earn coins at a significant percentage rate of a GPU rig, then Litecoin is serving its purpose.  You have to keep in mind that a $1,000 CPU mining Bitcoin is going to take 60 years to find a block, while a $1,000 GPU rig will take about 2 months.  The CPU rig is .2% as efficient as the GPU rig.

Lots of gibberish on this thread.    A typical current generation quad core cpu will produce 18MH/s a similarly priced (and higher power consumption) GPU will produce perhaps 320 MH/s.    ~20x is nowhere near 500x.

But a $1,000 Bitcoin GPU rig is going to produce over 1GH/s, not 320 MH/s.  So while my memory of what a good CPU will do for Bitcoin might be fuzzy (haven't done it), the overall point remains the same.  GPU mining on BTC has made CPU mining worthless, a money losing endeavor.  All the while, if GPU mining on Litecoin is as good as the rumors claim, CPU mining is still very much worthwhile.

[Ahimoth]

Anyone like crunching numbers? What would the price of LTC need to be in order to make GPU mining worthwhile? I don't think we're there, but like I said, I haven't run the numbers at all.

easy.. the same rig on bitcoin would make $5.17 daily, whereas on litecoin it would make $6.11 daily. This is according to allchains.info.

I guess everyone is ignoring my math that it is currently more profitable to mine LTC on a gpu rig than it is to mine bitcoins on that same rig.

Admittedly this is with the gpu miner kept private. If the gpu miner is released to the public, the ltc difficulty will likely increase, making the profit margin smaller, or putting bitcoin back in the lead.

[Schwede65]

I guess everyone is ignoring my math that it is currently more profitable to mine LTC on a gpu rig than it is to mine bitcoins on that same rig.

Admittedly this is with the gpu miner kept private. If the gpu miner is released to the public, the ltc difficulty will likely increase, making the profit margin smaller, or putting bitcoin back in the lead.

--- in the quote bold by me ---


that may be the truth...

you can post this the whole day long...

but who cares about a private software and the math with it, especially everyone...

[notme]

I guess everyone is ignoring my math that it is currently more profitable to mine LTC on a gpu rig than it is to mine bitcoins on that same rig.

Admittedly this is with the gpu miner kept private. If the gpu miner is released to the public, the ltc difficulty will likely increase, making the profit margin smaller, or putting bitcoin back in the lead.

--- in the quote bold by me ---


that may be the truth...

you can post this the whole day long...

but who cares about a private software and the math with it, especially everyone...

Right, we can't verify your numbers without access to said miner.

[Schwede65]

I guess everyone is ignoring my math that it is currently more profitable to mine LTC on a gpu rig than it is to mine bitcoins on that same rig.

Admittedly this is with the gpu miner kept private. If the gpu miner is released to the public, the ltc difficulty will likely increase, making the profit margin smaller, or putting bitcoin back in the lead.

--- in the quote bold by me ---


that may be the truth...

you can post this the whole day long...

but who cares about a private software and the math with it, especially everyone...

Right, we can't verify your numbers without access to said miner.

yeah, you, Ahimoth, claim to have math, but the only thing you do: start stirring the rumor pot.

Edit:
quote/Ahimoth: "A gpu rig consisting of 69xx series gpus can produce 998kh @ 920 watts"

this is indeed some hot air, because noone is able to compare it to btc-mining:
the nebulous 69xx-rig

[Ahimoth]

I can supply a picture of the rig if you like, but I know that still won't satisfy. Hell I could even make a video of the rig, and then me starting the miner, and showing hashrate at the pool of your choice, and most of you still wouldn't beleive me. Oh well, I was trying to be helpful by giving coblee some facts, so he could determine if a gpu miner for scrypt was enough of a threat to be concerned about, but it seems nobody wants to hear it. I give up...

[michaelmclees]

I can supply a picture of the rig if you like, but I know that still won't satisfy. Hell I could even make a video of the rig, and then me starting the miner, and showing hashrate at the pool of your choice, and most of you still wouldn't beleive me. Oh well, I was trying to be helpful by giving coblee some facts, so he could determine if a gpu miner for scrypt was enough of a threat to be concerned about, but it seems nobody wants to hear it. I give up...

I would very much like to see a video of it pointing at pool-x.

[Schwede65]

I can supply a picture of the rig if you like, but I know that still won't satisfy. Hell I could even make a video of the rig, and then me starting the miner, and showing hashrate at the pool of your choice, and most of you still wouldn't beleive me. Oh well, I was trying to be helpful by giving coblee some facts, so he could determine if a gpu miner for scrypt was enough of a threat to be concerned about, but it seems nobody wants to hear it. I give up...

a first little step would be to know, which 69xx-cards are inside this nebulous rig...
then i could do some math and compare btc- and ltc-mining wih this rig...
i don't want to have any videos of this 

btw: "to be helpful" sounds just like some propaganda...

[dayfall]

I have little invested in Litecoin, but I say we try changing algorithms.  As GPU mining is no threat right now (especially true if someone releases a GPU miner) we can set the switch over date far enough into the future to give enough time for testing and for people to upgrade.

Of course, we first must find out how the current algorithm has failed in order to make a better one.

[coblee]

Please dial it down everyone. Ahimoth and mtrlt, if you can make a video that's great. And can you give me more details on hashrate and which video cards?

[coblee]

@Coblee

There's no GPU miner for LTC and they know it. Nothing more than FUD and if Ahimoth wants to throw his reputation on a grenade for Coinhunter then so be it.

Think about it, as bad as Coinhunter despises you  and envies Litecoin, do you think for a second he would sit on a GPU miner that would devestate it? Not a chance.

~BCX~

I've talked to mtrlt about. CoinHunter doesn't control him. And he's in it just for profit. He's making more money with his GPUs mining litecoin than bitcoin. So he won't release it without being compensated somehow.

It's true that this could all be FUD, but I respect Ahimoth enough to believe that he wouldn't be lying about this just to spread FUD.

[ThiagoCMC]

@Coblee

There's no GPU miner for LTC and they know it. Nothing more than FUD and if Ahimoth wants to throw his reputation on a grenade for Coinhunter then so be it.

Think about it, as bad as Coinhunter despises you  and envies Litecoin, do you think for a second he would sit on a GPU miner that would devestate it? Not a chance.

~BCX~

I've talked to mtrlt about. CoinHunter doesn't control him. And he's in it just for profit. He's making more money with his GPUs mining litecoin than bitcoin. So he won't release it without being compensated somehow.

It's true that this could all be FUD, but I respect Ahimoth enough to believe that he wouldn't be lying about this just to spread FUD.

Ahimoth has every reason in the world to help spread the FUD and hurt Litecoin.

Ahimoth is the one who made the statement he can post a video of it, so I'm calling him out on it.


~BCX~

Yes, he needs to post some proof... Otherwise this is just the most recent scam from CH... That jerk.

[CoinHunter]

I see nothing correct in your Hashing Algorithm, i've implemented 2.5 faster Version of miner for it (CPU) and due lack of time and profit for mining there is even 3x-8x better implementation of GPU miner for Solidcoin so it's nothing other

Yes I'm aware of the improvements that can be made. You'll see the recent economic changes factor in high end CPU/GPU capable of producing close to 3KH/w, maybe a bit over. By the end of January next year the algorithm assumes 4.5KH/w . So if you get your magnifying glass out again I'm sure you'll see something correct.

[coblee]

I talked to Ahimoth about his specs. Here they are:

Mainboard: MSI 890FXA-GD70
Processor: AMD Sempron 140
Memory: 2x1GB Corsair DDR3 1333mhz
GPUs: 4x XFX 6950 1GB stock shaders, watercooled, and clocked at 1000mhz core and 1250mhz memory
Power: Corsair AX1200

Hashspeeds:
LTC - 998kh/s (reaper)
BTC - 1624mh/s (cgminer)

Wattage (at the wall):
LTC - 920 watts average
BTC - 950 watts average

The machine makes 1.35 btc every day mining bitcoins.
And it makes 630 ltc every day mining litecoins. At the .0024 exchange rate, that comes out to be 1.51 btc.
So it makes about 10% more mining litecoins as oppose to bitcoins.

[k9quaint]

I wouldn't spend much time on assertions from the Solidcoin camp without seeing the source code. Too many broken promises and sketchy behavior.

Occam says it is probably cut and pasted code with the licenses removed. There is probably bug in the hash rate display (again) making them think they are mining fast. Or they just made the whole thing up.

[drakahn]

lol, i've gone from not caring about to outright disliking solidcoin, mostly due to the loudmouth idiots that support it, and the trolls that attack btc-e chat from the solidcoin irc/forums, not people i would join.

[CoinHunter]

Ahimoth has every reason in the world to help spread the FUD and hurt Litecoin.

Ahimoth is the one who made the statement he can post a video of it, so I'm calling him out on it.

Yeah the king of liars crapcoinpress is calling out someone who everyone else would say is honest and decent. Get the popcorn folks because he's about to pop another vein. Fire up the geforce2 mx army Danny boy.

[CoinHunter]

lol, i've gone from not caring about to outright disliking solidcoin, mostly due to the loudmouth idiots that support it, and the trolls that attack btc-e chat from the solidcoin irc/forums, not people i would join.

Yeah I've seen your "well reasoned" chats on BTC-e. They go something like this "someone said blah so I believe them". Nice work there. The solidcoin community is going to need to take a while to recover from the news that someone of your caliber will not be joining us. With all your wisdom and experience it's a sad day for our little community!

[CoinHunter]

lol, i've gone from not caring about to outright disliking solidcoin, mostly due to the loudmouth idiots that support it, and the trolls that attack btc-e chat from the solidcoin irc/forums, not people i would join.

Yeah I've seen your "well reasoned" chats on BTC-e. They go something like this "someone said blah so I believe them". Nice work there. The solidcoin community is going to need to take a while to recover from the news that someone of your caliber will not be joining us. With all your wisdom and experience it's a sad day for our little community!

Please continue on your Bipolar defeatist rants.....

This is the spokesman, the founder of Solidcoin. This is what you expect any reputable business to want to do business with.

You have been successfully manipulated by BCX, I'm laughing my ass off at you Coinhunter.

Please continue LOL....

Thanks for playing the part in spreading the message of SolidCoin. No publicity is bad publicity remember You've been manipulated by coinhunter into caring.

[CoinHunter]

The only publicity brought forward is that Solidcoin is controlled by a Bipolar wannabe.

Publicity is publicity. It's thanks to people like you that have helped propel SC into the #2 cryptocurrency. Thanks again, keep caring, we appreciate it.

[dishwara]

Anyone can explain me why i am getting this error when using on litecoin?

2012-02-17 22:01:10 Error 6 getting work. See http://curl.haxx.se/libcurl/c/libc
url-errors.html for error code explanations.
2012-02-17 22:01:10 Couldn't connect to server. Trying again in a few seconds...

I tried website mentioned, but cant find.
I used reaper 12 from http://wiki.solidcoin.info/wiki/Reaper

Bump.....

I will be happy if coinhunter or ahimoth help me to solve it.

[CoinHunter]

Bump.....

I will be happy if coinhunter or ahimoth help me to solve it.

Reaper v12 doesn't support litecoin. Apparently v13 will.

[MCWey8]

What is known is that the original thread claiming artforz and coblee were GPU mining was a FUD campaign.

What we are hearing now is that mtrlt is GPU mining and will not release code without compensation.



Why would CH want to let us all know this ? Why would CH tell us that the developer for their miner is taking advantage of other crypto currencies ?

Doesn't this show that taking advantage of people and open source projects is what they stand for ?

Or can they really believe that hurting others will highlight their coins "greatness" ?




I am a noob. I am not an expert. But thanks to this LTC fiasco, Solidcoin looks foolish, greedy and the farthest thing anyone would want from a OPEN currency. 

[drakahn]

lol, i've gone from not caring about to outright disliking solidcoin, mostly due to the loudmouth idiots that support it, and the trolls that attack btc-e chat from the solidcoin irc/forums, not people i would join.

Yeah I've seen your "well reasoned" chats on BTC-e. They go something like this "someone said blah so I believe them". Nice work there. The solidcoin community is going to need to take a while to recover from the news that someone of your caliber will not be joining us. With all your wisdom and experience it's a sad day for our little community!

You seem twice as smart as the trolls that support you, which says a lot I think. You're little community has my best wishes lol.

[CoinHunter]

What is known is that the original thread claiming artforz and coblee were GPU mining was a FUD campaign.

What we are hearing now is that mtrlt is GPU mining and will not release code without compensation.
Why would CH want to let us all know this ? Why would CH tell us that the developer for their miner is taking advantage of other crypto currencies ?

Doesn't this show that taking advantage of people and open source projects is what they stand for ?

Or can they really believe that hurting others will highlight their coins "greatness" ?
I am a noob. I am not an expert. But thanks to this LTC fiasco, Solidcoin looks foolish, greedy and the farthest thing anyone would want from a OPEN currency.  

So someone making a faster miner has to release it or they are "Taking advantage" of a cryptocurrency? Sad news indeed if that's the case. THANK YOU for your reasoned comments and your definitive stance on "I'm never touching that SolidCoin because one of the developers made a faster miner for another coin *snicker*" . It's unbiased heroes like you that make the world a better place!  

How about people blame coblee or the litecoin supporters for not coughing up anything? I paid mtrlt to release his SolidCoin miner and he did. But the brokeback mountain Litecoin supporters are so cheap they would rather believe everyone in the world is delusional except them.

[Vanderbleek]

Actually, I'd say that writing a faster miner and keeping it for your own use is adding to the security of the network, PROVIDED you are not using it to 51%. You're making it more expensive for people to attack the chain -- without the faster miner, people will have to purchase and run more hardware, or pay someone to develop software. Releasing it publicly puts everyone on equal footing, which is a hardware based level of security. If that was the case though, I don't know why anyone would post about it, unless you're simply trying to drum up drama.

[film2240]

Can someone send me the LTC GPU Miner via PM or on here please as I want to see some evidence and to test this myself.Thanks.I think it's not fair that a few people have the GPU miner while the rest are just CPU mining so to the person who does GPU mine is,either release the miner or do something else (I'm not sure what this is but thats for others to decide).

Is it or is it not possible to GPU mine LTC?

[film2240]

Can someone send me the LTC GPU Miner via PM or on here please as I want to see some evidence and to test this myself.Thanks.I think it's not fair that a few people have the GPU miner while the rest are just CPU mining so to the person who does GPU mine is,either release the miner or do something else (I'm not sure what this is but thats for others to decide).

Is it or is it not possible to GPU mine LTC?

No problem. You can obtain that Miner from mtrlt.
Just pay him 1 million $.

Sounds like his miner is a closely guarded secret then if he has the nerve to charge a $1 million for a mining app.I've never heard of 1 preson paying for a $1 million.Unless they're simply saying no chance of getting their miner instead (which I think is what they meant).

Also noticed that mtrit hangs about on Solidcoin talk as well: http://solidcointalk.org/user/374-mtrlt/
He created reaper miner and luuminer for Solidcoin mining, I just saw.

[Schwede65]

The machine makes 1.35 btc every day mining bitcoins.
And it makes 630 ltc every day mining litecoins. At the .0024 exchange rate, that comes out to be 1.51 btc.
So it makes about 10% more mining litecoins as oppose to bitcoins.

now only a few guys are ltc-gpu-mining and the 10/20%-profit depends on this private software...

it is only a snapshot of nice profit for only a few...

what will happen when this reaper13 is public?

one gpu-mining-circle of 2016 blocks may double the diff or just more...
then many will change the mined coins into btc, because btc-rigs would mine ltc with their power and most of them have to pay for electricity...

so the diff is up and the price is down...
what would happen to the ltc-gpu-miner?
they will quickly go back to btc-mining...

we have had similar settings with the dark pool(s) - botnets or private ltc-gpu-miner - who really knows...

additionally: ltc has a possible defense of a 51%-attack, when it should happen many gpu-miner who earn and like ltc would do ltc-gpu-mining in a defense-pool and the attacking dark pool can jump in the lake  

i think litecoin should not be afraid of a public reaper13...

yeah, reaper13, welcome to ltc  

[pla]

Those of you welcoming GPU mining for LTC/SC have kinda missed the point of why those currently hold the #2/#3 spot in the cryptocurrency world...

I have a decent gaming rig, which I can put to work GPU-mining BTC.  I have no need for more than one decent gaming rig, nor do I have even the faintest excuse to deck it out with quad 6990s.  I do, however, have access to somewhere around twenty i5/i7 cores, all sitting around doing nothing very useful 95% of the time.  I suspect, in that regard, I represent a fairly typical BitCoin enthusiast.

I became interested in mining a second cryptocurrency only because tennebrix (and then others) came up with a way to make CPU mining viable again... I figured, why not put the two or three decent machines I run at home, as well as a couple strays at my shop, onto a useful task instead of simply letting them sit around growing slowly more obsolete by the day?  I suspect I represent a fairly typical LTC/SC enthusiast, in that regard.

Put bluntly, if GPU mining becomes viable for LTC and/or SC, their entire raison d'etre vanishes.  We don't need to decide if we should react if mtrlt releases Reaper13 and it really does work 25x faster on GPUs; We need to decide how to react, and preferably have our changes ready to roll out on the very same day.  And while "do nothing" always counts as an option, in this case it counts as an option that effectively dooms this entire branch of BTC variants.

And yes, before anyone points out the various other problems with BitCoin that various spinoffs address, I understand this doesn't reduce solely to mining hardware issues; But really - It does, so far as most people care.

[tacotime]

If you want to believe me, then I can vouch for mtrlt's gpu miner being significantly more efficient than any current cpu miner for scrypt.

From what I know of the gpu miner, option 3 of modifying the scrypt parameter will have minimal impact. The pad size did not seem to matter much, and can be compressed for lack of a better word, with on the fly value reconstruction. So any increase in pad size will have a relatively equal impact on cpu miners until you exceed their cache size, at which point, gpus may become even more efficient.

I think you will be stuck with option 2, finding a completely different hashing algorithm.

Are you saying he has disproved the sequential memory hardness for the ROMix algorithm from the original scrypt paper?  I don't see why mtrlt couldn't supply us with at least some of the mathematics behind his algorithm.

If mtrlt has really completed this code, he could easily create an account on a pool with a random username and password, start mining, and have someone log on and verify that he's actually get 1M/s with four miners.  It's really at no loss to him, he would only need to mine for a few minutes for the hash rate to be apparent to the other person.  Why hasn't he done this?

[CoinHunter]

Those of you welcoming GPU mining for LTC/SC have kinda missed the point of why those currently hold the #2/#3 spot in the cryptocurrency world...

If you're going by market cap, its #1 Bitcoin <big gap> #2 SC <gap> #3 NMC, #4 LTC

Put bluntly, if GPU mining becomes viable for LTC and/or SC, their entire raison d'etre vanishes.  We don't need to decide if we should react if mtrlt releases Reaper13 and it really does work 25x faster on GPUs; We need to decide how to react, and preferably have our changes ready to roll out on the very same day.  And while "do nothing" always counts as an option, in this case it counts as an option that effectively dooms this entire branch of BTC variants.

Actually the SolidCoin hash was developed to be fairly equal in performance on GPUs and CPUs, watt for watt. It is currently delivering that and has been for some time (with a small favor to CPUs). SolidCoin takes all consumer hardware that is viable so we can let the widest range of people mine it fairly. Unlike Bitcoin which is going to be FPGA soon and Litecoin (which was supposed to be CPU only and is now a GPU coin), we want everyone to be able to mine.

[Bitinvestor]

Those of you welcoming GPU mining for LTC/SC have kinda missed the point of why those currently hold the #2/#3 spot in the cryptocurrency world...

I have a decent gaming rig, which I can put to work GPU-mining BTC.  I have no need for more than one decent gaming rig, nor do I have even the faintest excuse to deck it out with quad 6990s.  I do, however, have access to somewhere around twenty i5/i7 cores, all sitting around doing nothing very useful 95% of the time.  I suspect, in that regard, I represent a fairly typical BitCoin enthusiast.

I became interested in mining a second cryptocurrency only because tennebrix (and then others) came up with a way to make CPU mining viable again... I figured, why not put the two or three decent machines I run at home, as well as a couple strays at my shop, onto a useful task instead of simply letting them sit around growing slowly more obsolete by the day?  I suspect I represent a fairly typical LTC/SC enthusiast, in that regard.

Put bluntly, if GPU mining becomes viable for LTC and/or SC, their entire raison d'etre vanishes.  We don't need to decide if we should react if mtrlt releases Reaper13 and it really does work 25x faster on GPUs; We need to decide how to react, and preferably have our changes ready to roll out on the very same day.  And while "do nothing" always counts as an option, in this case it counts as an option that effectively dooms this entire branch of BTC variants.

And yes, before anyone points out the various other problems with BitCoin that various spinoffs address, I understand this doesn't reduce solely to mining hardware issues; But really - It does, so far as most people care.

I see. You don't care about Litecoin, you just want some free money from your old stuff, just like the botnets. If that's the only reason for Litecoin's existence then why would anybody buy litecoins? To feed you and the botnets?

A currency exists to facilitate the storage and transfer of wealth and litecoin is not fit for this purpose while half of it is mined by botnets. They could attack at any moment. Get rid of this silly botnet mining and make Litecoin a respectable currency.

[Syke]

SolidCoin takes all consumer hardware that is viable so we can let the widest range of people mine it fairly.

$7 in electricity (not even counting the hardware depreciation costs) to generate a coin that's worth $.04. That sure is a very twisted meaning of "fair". I see coinotron is up to 28 miners. That's nearly 60 total miners in the world mining SolidCoin!

[Schwede65]

Those of you welcoming GPU mining for LTC/SC have kinda missed the point of why those currently hold the #2/#3 spot in the cryptocurrency world...

haven't you realized, that sc is just cpu AND gpu-minable?

yeah, i mined sc2 with my cpu's, then the reaper came up and i mined with cpu AND gpu...

first the sc-gpu-mining was more profitable compared to btc, but this lasted not very long and i went back from sc-gpu-mining to btc-gpu-mining...

some "enthusiasts" stayed on to gpu-mine the unprofitable currency...
...others may call them "informed insider"  

atm sc-mining is totally wasting energy, if you have to pay for power...

whats your problem now with public ltc-gpu-mining?

the best paradigm - cpu- + gpu-mining - for ltc is sc...

atm its profitable to mine ltc with gpu's, but diff will go up quickly and the gpu-profit is away...

the problem i see is the efficiency:
sc: cpu is slightly more efficient then gpu
ltc: gpu is more efficient then cpu
factor 2:1 is realistic for mining-rigs, where you have to count only the extra-watt of cpu-ltc-mining in comparison to gpu-ltc-mining/complete rig

when many "ltc-gpu's" go back to btc, then there is a very high diff (respectively low price) and the cpu-mining is very unprofitable, we have seen this with tbx and fbx, nearly noone is mining them...

the conclusion is to switch to the sc2-algo or we find a better gpu-hostile-algo...

but how long will it last up to a talented programmer, who will find a way to gpu-mine the new algo more efficiently then cpu...

then we are back at the starting point...

[Schwede65]

I talked to Ahimoth about his specs. Here they are:

Hashspeeds:
LTC - 998kh/s (reaper)
BTC - 1624mh/s (cgminer)

Wattage (at the wall):
LTC - 920 watts average
BTC - 950 watts average

The machine makes 1.35 btc every day mining bitcoins.
And it makes 630 ltc every day mining litecoins. At the .0024 exchange rate, that comes out to be 1.51 btc.
So it makes about 10% more mining litecoins as oppose to bitcoins.

without energy-costs, because it differs so much - http://allchains.info/calc.html

LTC - 998kh/s // 920 watts: $4.354 (without energy-costs)
BTC - 1624mh/s // 950 watts: $4.874 (without energy-costs, but the more watt included, so: 1573 mh/s)

atm: btc-gpu-mining is 11.9 % more profitable then ltc-gpu-mining

[pla]

I see. You don't care about Litecoin, you just want some free money from your old stuff, just like the botnets. If that's the only reason for Litecoin's existence then why would anybody buy litecoins? To feed you and the botnets?

Not quite true - I would sincerely love to see a modern decentralized cryptocurrency make old-school notions of fiat currency like the dollar and euro completely obsolete.  I didn't join this community back when BTC had a value of $0.04 each (nor do I mine LTC, currently worth less than a US penny each) hoping to strike it rich.   

At worst, you could say that I believe in hedging my bets.  I won't buy $4000 in GPUs just to help seed a cyptocurrency, and if I make "some free money from your old stuff", hey, cool.

That said, we post in a community who already understands all of this (and still has legitimate disagreements - bordering on holy wars - on how it should all work).  But fiat currency or not, any "money" other than food, shelter, and sex, has no value except what a sufficiently large population agree it has.  We need to consider what the average Joe sees in this - And Joe has no reason to take an interest and play along if he can't join us without an unreasonable barrier to entry.

Bitcoin passed that barrier quite a few months ago, and today, "Joe" sees it as a subject of ridicule - "Oh, you mean that thing where the Russian mafia buys up all the ATI cards so they can launder their money?" (and don't even get me started on how many idiots haven't the faintest clue about the real meaning of a Ponzi scheme).  A CPU-only (or at least, GPU/ASIC unfriendly) BTC variant, I believe, has a lot of potential to let all the latecomer Joes try to get into the game again.

haven't you realized, that sc is just cpu AND gpu-minable?

Haven't you (all) realized that if you can do it for LTC, you can do it for SC?  Though different core algorithms, they use the same underlying assumptions about the cost of memory accesses to limit GPU performance - Which mtrlt may have proven false (we still have no proof of that).  I mentioned both LTC and SC in my post because I mean to refer to both.  Nothing short of a "hard" serial algorithm will prevent GPUs from doing it better than CPUs; that, however, would tend to break the whole idea of a distributed currency (if 200 people can mine independently more efficiently than one person with a bigger rig, then most likely so can 200 ALUs vs one full CPU).

I don't really have an answer to this, but I think we need to discuss it without disintegrating into "my chosen BTC variant works better than yours".

[Schwede65]

haven't you realized, that sc is just cpu AND gpu-minable?

Haven't you (all) realized that if you can do it for LTC, you can do it for SC?  

now (all) can realize your noob-status...

very interesting for furthermore postings  

[pla]

now (all) can realize your noob-status...
very interesting for furthermore postings  

I would take that personally, if you had actually understood what I said.  Let me know when you learn to code, and I'll try to act hurt over your opinion of me.

I have no favorite horse in this race.  You would do well not to mock me when I point out that yours has a broken leg.

[Syke]

LTC - 998kh/s // 920 watts: $4.354 (without energy-costs)
BTC - 1624mh/s // 950 watts: $4.874 (without energy-costs, but the more watt included, so: 1573 mh/s)

atm: btc-gpu-mining is 11.9 % more profitable then ltc-gpu-mining

I can't speak to LTC efficiency, but those BTC wattage figures are using a very inefficient Bitcoin GPU miner. A good GPU system can get about double that performance for the same wattage.

[Schwede65]

now (all) can realize your noob-status...
very interesting for furthermore postings  

I would take that personally, if you had actually understood what I said.  Let me know when you learn to code, and I'll try to act hurt over your opinion of me.

I have no favorite horse in this race.  You would do well not to mock me when I point out that yours has a broken leg.

yeah, now we are at a coder contest...

i think i'm in the wrong movie...

you can't see the wood for the trees...

thanks for this very interesting posting...

[Schwede65]

LTC - 998kh/s // 920 watts: $4.354 (without energy-costs)
BTC - 1624mh/s // 950 watts: $4.874 (without energy-costs, but the more watt included, so: 1573 mh/s)

atm: btc-gpu-mining is 11.9 % more profitable then ltc-gpu-mining

I can't speak to LTC efficiency, but those BTC wattage figures are using a very inefficient Bitcoin GPU miner. A good GPU system can get about double that performance for the same wattage.

we can't compare apples and oranges, on the more efficient rig, you will do the btc- and ltc-mining with lower watt, because of the higher productivity of the rig...

[Schwede65]

now we can test the truth of the ltc-gpu-mining:

http://solidcoin.info/reaper.html

it works with my 5850 on http://www.litecoinpool.org

congrats!

[drakahn]

Its not useful though, i can mine enough btc to buy 3-10 times the amount of ltc this thing could mine

its just silly

[Vanderbleek]

Doesn't work for me, gives a kernel build error.

[shakti]

Its not useful though, i can mine enough btc to buy 3-10 times the amount of ltc this thing could mine

its just silly

Well yes, but cause this implementation depends most of GPU-memory speed i think this scrypt miner will run wit same/better results on Nvidia GPUs so it's not that worthless

[drakahn]

anyone got any results from an nvidia card?

[shakti]

anyone got any results from an nvidia card?

Nope, it's not source it's precompiled for 2 AMD chips, but theoreticaly if we get source it will perform ok on Nvidia.

[tatsuchan]

Running Windows 7, i5, Gigabyte AMD HD6850

DOES NOT WORK. Crash on start

[dishwara]

Error 28 getting work. See http://curl.haxx.se/libcurl/c/libcurl-errors.html for
 error code explanations.

[3phase]

Its not useful though, i can mine enough btc to buy 3-10 times the amount of ltc this thing could mine

its just silly

Did you miss a decimal point somewhere?
At current prices and difficulties it's almost par.

[Graet]

I had it running on a msi 6950 twin frozr at 310Khash,
it does work, but its a waste of time and power....

3phase if so not for long, checked the price of LTC in the last hour or so? lol

[tacotime]

Does not work with pools for me
To solo on windows:

1. Download litecoin daemon from github: https://github.com/coblee/litecoin/downloads
2. Go to C:\Users\{yourcomputer}\AppData\Roaming\litecoin\ and create litecoin.conf.
3. Put this in it:

Code:

# Network-related settings:
# Run on the test network instead of the real bitcoin network.
#testnet=1
# Connect via a socks4 proxy
#proxy=127.0.0.1:9050
# Use as many addnode= settings as you like to connect to specific peers
#addnode=69.164.218.197
#addnode=10.0.0.2:8333
# … or use as many connect= settings as you like to connect ONLY
# to specific peers:
#connect=69.164.218.197
#connect=10.0.0.1:8333
# Do not use Internet Relay Chat (irc.lfnet.org #bitcoin channel) to
# find other peers.
#noirc=1
# Maximum number of inbound+outbound connections.
#maxconnections=
# JSON-RPC options (for controlling a running Bitcoin/bitcoind process)
# server=1 tells Bitcoin to accept JSON-RPC commands.
#server=1
# You must set rpcuser and rpcpassword to secure the JSON-RPC api
rpcuser=user
rpcpassword=password
# How many seconds bitcoin will wait for a complete RPC HTTP request.
# after the HTTP connection is established.
rpctimeout=30
# By default, only RPC connections from localhost are allowed. Specify
# as many rpcallowip= settings as you like to allow connections from
# other hosts (and you may use * as a wildcard character):
#rpcallowip=10.1.1.34
#rpcallowip=192.168.1.*
# Listen for RPC connections on this TCP port:
rpcport=9332
# You can use Bitcoin or bitcoind to send commands to Bitcoin/bitcoind
# running on another host using this option:
rpcconnect=127.0.0.1
# Use Secure Sockets Layer (also known as TLS or HTTPS) to communicate
# with Bitcoin -server or bitcoind
#rpcssl=1
# OpenSSL settings used when rpcssl=1
rpcsslciphers=TLSv1+HIGH:!SSLv2:!aNULL:!eNULL:!AH:!3DES:@STRENGTH
rpcsslcertificatechainfile=server.cert
rpcsslprivatekeyfile=server.pem
# Miscellaneous options
# Set gen=1 to attempt to generate bitcoins
gen=0
# Use SSE instructions to try to generate bitcoins faster. For muliple core processors.
#4way=1
# Pre-generate this many public/private key pairs, so wallet backups will be valid for
# both prior transactions and several dozen future transactions.
keypool=100
# Pay an optional transaction fee every time you send bitcoins. Transactions with fees
# are more likely than free transactions to be included in generated blocks, so may
# be validated sooner.
paytxfee=0.00
# Allow direct connections for the ‘pay via IP address’ feature.
#allowreceivebyip=1
# User interface options
# Start Bitcoin minimized
#min=1
# Minimize to the system tray
#minimizetotray=1

4. Make this your litecoin.conf in the reaper directory:

Code:

host localhost
port 9332
user user
pass password

protocol litecoin

worksize 256
aggression 18
threads_per_gpu 1
sharethreads 20

5. Run litecoind.exe and let it catch up with the network.
6. Run reaperDEMO.exe.  If it throws a kernel error, go into the directory.  There should be a litecoin-reaperv13.XXXXX.bin file where XXXXX is your architecture.  Rename litecoin-reaperv13.Cayman.bin to litecoin-reaperv13.XXXXX.bin.  Reaper should work fine now.

[Graet]

works fine on lc.ozco.in by ip but not url I have found

host 67.210.248.11
port 9332
user Graet.5
pass p

is all i changed in litecoin.conf

[dishwara]

Increasing gpu clock & memory clock increases hash rate, instead of just gpu clock

[illpoet]

lol this demo is broken for me.

[Tittiez]

lol this demo is broken for me.

Only works for 58xx and 69xx because its precompiled for them.

[Balthazar]

If more effective GPU miner will be released, simple changes in algorithm will make it completely unusable. For example, we can use bcrypt() result as salt. I.e. add stage in hashing process.

Current algorithm is:

1) Calculate B = SHA256(A)
2) Calculate C = scrypt(B)
3) Calculate D = SHA256(B, C)
4) Return D

Probably future algorithm:

1) Calculate B = SHA256(A)
2) Calculate C = scrypt(B)
4) Calculate D = bcrypt(C)
3) Calculate E = SHA256(B, D)
4) Return E

Like scrypt(), bcrypt() is also using many pseudo-random operations with memory during encryption process.

[shakti]

If more effective GPU miner will be released, simple changes in algorithm will make it completely unusable. For example, we can use bcrypt() result as additional salt. I.e. add stage in hashing process.

Current algorithm is:

1) Calculate B = SHA256(A)
2) Calculate C = scrypt(B)
3) Calculate D = SHA256(B, C)
4) Return D

Probably future algorithm:

1) Calculate B = SHA256(A)
2) Calculate C = scrypt(B)
4) Calculate D = bcrypt(C)
3) Calculate E = SHA256(B, D)
4) Return E

Like scrypt(), bcrypt() is also using many pseudo-random operations with memory during encryption process.

1) Well i'm sure there is NO WAY to create an Algorythm that will NEVER better implemented on some piece of future hardware.
2) LTC is used by bot-nets to generate some cash, and aslong it is in this situation it will never be accepted as "stable" currency.
3) The limits on how good current Algoritm can be implemented on GPU i've calculated somewhere above, on common hardware  best can be Nvidia GT 590 with smthg like 1.2 MH/s (unreachable maximum).  Is this that dangerous for LTC ? i think NO.

I think we should leave it atm as it is and spare afford for "fixing" situation for other more dangerous situation.
P.S. i think GPU mining for LTC can even be good for LTC stabilizing network hashrate. My idea is do nothing.

[coblee]

Given that it's currently not worth it to mine LTC using GPU, having a GPU miner out is not going to change much. But there are few potential problems I can think of:

1) This puts a cap on LTC price. When LTC price rises to make GPU mining profitable, we will see a bunch of people switching their GPU farms to Litecoin and sell the mined litecoins for bitcoins. This will put a downward pressure on Litecoin price. This is not necessarily a bad thing, because price doesn't matter that much.

2) Could lead to wild swings in difficulty as GPU miners move in and out of Litecoin mining. This will be similar to what happened with Namecoin before the merged mining. But since Litecoin retargets at 1/4 the time as compared to Bitcoin (3.5 days as oppose to 2 weeks), the swings shouldn't be that painful.

3) GPU mining makes it easier to 51% the chain. It would be easy for a decently sized GPU farm to 51% the chain.

I think I'm most worried about the last one.

[Balthazar]

My idea is do nothing.

OP_NOP is the simplest solution of any problem. 

At the moment mining on GPU isn't effective for LTC and we can do nothing. But we must think about future, anyway.

[shakti]

Given that it's currently not worth it to mine LTC using GPU, having a GPU miner out is not going to change much. But there are few potential problems I can think of:

1) This puts a cap on LTC price. When LTC price rises to make GPU mining profitable, we will see a bunch of people switching their GPU farms to Litecoin and sell the mined litecoins for bitcoins. This will put a downward pressure on Litecoin price. This is not necessarily a bad thing, because price doesn't matter that much.

2) Could lead to wild swings in difficulty as GPU miners move in and out of Litecoin mining. This will be similar to what happened with Namecoin before the merged mining. But since Litecoin retargets at 1/4 the time as compared to Bitcoin (3.5 days as oppose to 2 weeks), the swings shouldn't be that painful.

3) GPU mining makes it easier to 51% the chain. It would be easy for a decently sized GPU farm to 51% the chain.

I think I'm most worried about the last one.

well without decent network hashrate it can be attacked easy by any botnet ... having GPU miner makes it cheaper to get better hashrate.
LTC is designed from start on to be smthg like 1/4 of Bitcoin ? bitcoins silver )) so we can't go around of it both currencies will be dependent on eachother.
there will be couple of Miners on Nvidia, cause it makes same hashrate as ATI for scrypt. so i think if network hasrate goes up with GPU miners it will be not lead to wild swings. and even better protection for 51% attack from botnet. Sure atm we have dangerous time where network hasrate is low and GPU miner makes it possible to attack the chain, but shouldn't we just try to make Network stronger insted of swing it with changes?

[tacotime]

Something I've wondered:

Why are you using N=1024, r=1, and p=1 for scrypt?  Why didn't the recommended values from the paper, N=1024, r=8, p=1 get used?

[tacotime]

3) GPU mining makes it easier to 51% the chain. It would be easy for a decently sized GPU farm to 51% the chain.

I think I'm most worried about the last one.

The addition of GPU mining to bitcoin actually enhanced security of the coin.  I saw this discussed on BTCe with Artforz and it was generally held that the more expensive the mining hardware required, the more reinforced the bitcoin chain becomes.

What I think would really add a lot to LTC is to implement a chain that halves in six months but does so incrementally, that is, every block or 200 blocks or whatever decreases a certain percent, with 50% block size at six months.  Liquidcoin has proved this to be easily possible.

[dishwara]

I am not a follower of coin hunter or solid coin & all their stuffs...........

I saw in my own eyes, a 5870 mining litecoins, & i put screen shot.
For those who still saying no proof, better download & try urself.
http://solidcoin.info/reaper.html

First they CPU mined bitcoins & thought nothing is there other than CPU, then GPU mining came to bitcoins & even FPGA.....

The question now is first it was told its only CPU mining, but now GPU also can mine them.
Profit or loss is another question. Can GPU mine litecoins? Yes.

Now what Litecoin developers going to do about GPU mining?  

[pooler]

Current algorithm is:

1) Calculate B = SHA256(A)
2) Calculate C = scrypt(B)
3) Calculate D = SHA256(B, C)
4) Return D

Not really. SHA256 is part of scrypt. The sequence looks more like this:

1) PBKDF2 using HMAC-SHA-256
2) Memory-hard mixing loop using salsa20/8
3) PBKDF2 using HMAC-SHA-256

Something I've wondered:

Why are you using N=1024, r=1, and p=1 for scrypt?  Why didn't the recommended values from the paper, N=1024, r=8, p=1 get used?

If I remember correctly, ArtForz said that the parameters (1024, 1, 1) resulted in a lower GPU/CPU performance ratio.
Some analysis by him can be found here: https://bitcointalk.org/index.php?topic=45849.0

http://solidcoin.info/reaper.html

What looks interesting is that they still claim the SC2 algorithm to be GPU-resistant. I'm not at all convinced. Any technical opinion on this?

[Balthazar]

Current algorithm is:

1) Calculate B = SHA256(A)
2) Calculate C = scrypt(B)
3) Calculate D = SHA256(B, C)
4) Return D

Not really. SHA256 is part of scrypt. The sequence looks more like this:

1) PBKDF2 using HMAC-SHA-256
2) Memory-hard mixing loop using salsa20/8
3) PBKDF2 using HMAC-SHA-256

Yes, salsa20/8 generates "password salt" for second PBKDF2 call. I mean, that new algorithm can use bcrypt() before second PBKDF2 call. This will be VERY slow and L1 cache-dependent. 

[localhost]

I saw in my own eyes, a 5870 mining litecoins, & i put screen shot.
For those who still saying no proof, better download & try urself.
http://solidcoin.info/reaper.html

Doesn't work for me: always times out when trying to reach the pool...

[shakti]

I saw in my own eyes, a 5870 mining litecoins, & i put screen shot.
For those who still saying no proof, better download & try urself.
http://solidcoin.info/reaper.html

Doesn't work for me: always times out when trying to reach the pool...

hostname used should be without prefix http://

[shakti]

http://solidcoin.info/reaper.html

What looks interesting is that they still claim the SC2 algorithm to be GPU-resistant. I'm not at all convinced. Any technical opinion on this?

It's not GPU resistant, but random reads on constant 4MB buffer make the difference of CPU/GPU slightly lower cause GPU lucks on a lot of cache. But it's still 4-6 times faster on GPU as on CPU

[localhost]

Doesn't work for me: always times out when trying to reach the pool...

hostname used should be without prefix http://

I tried both: with http, without http, also with IP instead of host name, different ports (using pool-x so I could try port 80, 8080, etc), nothing worked

[3phase]

Given that it's currently not worth it to mine LTC using GPU, having a GPU miner out is not going to change much. But there are few potential problems I can think of:

1) This puts a cap on LTC price. When LTC price rises to make GPU mining profitable, we will see a bunch of people switching their GPU farms to Litecoin and sell the mined litecoins for bitcoins. This will put a downward pressure on Litecoin price. This is not necessarily a bad thing, because price doesn't matter that much.

2) Could lead to wild swings in difficulty as GPU miners move in and out of Litecoin mining. This will be similar to what happened with Namecoin before the merged mining. But since Litecoin retargets at 1/4 the time as compared to Bitcoin (3.5 days as oppose to 2 weeks), the swings shouldn't be that painful.

3) GPU mining makes it easier to 51% the chain. It would be easy for a decently sized GPU farm to 51% the chain.

I think I'm most worried about the last one.

Number 2 is the biggest danger. With the next Litecoin retarget, as long as price stays above 0.0015, it will be more profitable to mine LTC (yes, with that closed source miner). Maybe not this time around, but by the next time when more people will have heard of it, you could get a few hundred MH/s switching to LTC mining, reach retarget with a 4x difficulty in a few hours, and then they leave, which will then make it very difficult (2 weeks or more) for the rest of the miners to fix by retargeting to a lower (0.25x) difficulty. Also take into account that, at this point, it will be largely unprofitable to mine LTC even with GPUs, so you might have even more miners shutting down.

The difficulty swings that happen because of exchange rates have been proven to be non-converging. Profitable difficulty periods get shorter and unprofitable periods get longer. It happened to NMC, I0C, IXC, FBX and TBX in the same way.  Eventually the chain dies, unless merged mining takes over. In LTC's case this is not possible.

We shall see. It will be at least interesting to watch.

[localhost]

I saw in my own eyes, a 5870 mining litecoins, & i put screen shot.
For those who still saying no proof, better download & try urself.
http://solidcoin.info/reaper.html

Doesn't work for me: always times out when trying to reach the pool...

On a side note, anyone knows why the GPU miner tries to connect to load.squidnet.org (96.8.126.110) from port 51100 to port 12000?

[Fuzzy]

Doesn't work for me: always times out when trying to reach the pool...

hostname used should be without prefix http://

I tried both: with http, without http, also with IP instead of host name, different ports (using pool-x so I could try port 80, 8080, etc), nothing worked

Same here, tried 4 pools, nothing would connect.

A hoax to instill uncertainty in a competing crypto currency? Given how outspoken the SC team are against LTC, I don't see why they are holding back with Demo versions if they have a real opportunity to cripple a competitor.

[localhost]

I tried both: with http, without http, also with IP instead of host name, different ports (using pool-x so I could try port 80, 8080, etc), nothing worked

Same here, tried 4 pools, nothing would connect.

Since "localhost" was the default option, I even tried solo-mining: failed to connect too.

[dishwara]

u have to put it in litecoin.conf & just run reaperdemo.exe without any arguments.
Litecoin.conf for
host mine.pool-x.eu
port 9332
user urpoolname with worker like xxx.1
pass ur password for pool

[localhost]

u have to put it in litecoin.conf & just run reaperdemo.exe without any arguments.
Litecoin.conf for
host mine.pool-x.eu
port 9332
user urpoolname with worker like xxx.1
pass ur password for pool

That's what I did, it didn't work (timeout). Note that the pool wasn't down as my other worker could connect to it without problem.

And this doesn't explain why the miner sneakily connects to another pool, as I detailed in post 118.

[dishwara]

No idea. Its not connecting connecting sneakily another pool in my system.
It seems your download is affected with some virus or trojan or any other malwares.

I too got first timeout error, then weird server problem error, library error..........

[localhost]

No idea. Its not connecting connecting sneakily another pool in my system.
It seems your download is affected with some virus or trojan or any other malwares.

I did download from there, though: http://solidcoin.info/reaper.html. I don't have the file I downloaded on this very computer, I'll post md5sum of the file I grabbed tomorrow, if someone wants to compare with their own hash. Also, I didn't check what it tries to communicate to the pool, maybe it's just pinging and sending nothing. But there's some kind of connection attempt.

[Fuzzy]

I have Radeon 6950s on Win7 x64 bit, and this GPU miner doesn't actually work. It either crashes, or fails to connect.

Also, the fact that the LTC network hash rate DROPPED after the release of this "demo" suggests this is a HOAX, and not actually able to submit legit shares for mining LTC

[Rubberduckie]

It works for me,solo mined 2 blocks so far

(mining with a 6970 @ 262 Kh/s)

[localhost]

No idea. Its not connecting connecting sneakily another pool in my system.
It seems your download is affected with some virus or trojan or any other malwares.

I did download from there, though: http://solidcoin.info/reaper.html. I don't have the file I downloaded on this very computer, I'll post md5sum of the file I grabbed tomorrow, if someone wants to compare with their own hash.

If anyone wants to compare with the files they downloaded, here are my md5 hashes

Code:

7220844fab32072fc4279436f330bb76  litecoin-reaperv13_demo.zip
7bc0ee636b3b83484fc3b9348863bd22  litecoin-reaperv13_demo\litecoin-reaper.cl
0f6e06a7cd747d317f7c8b441e0cd946  litecoin-reaperv13_demo\litecoin.conf
5757f08f18556c6cf1beabb51579cfa1  litecoin-reaperv13_demo\curl.dll
53cf7caa93ca6d827061d67719a99c34  litecoin-reaperv13_demo\litecoin-reaperv13.Cayman.bin
3cd768d7dd0874b8ea6639aa0ac03a5f  litecoin-reaperv13_demo\litecoin-reaperv13.Cypress.bin
544f3050ffe55e6b423695331e581bbd  litecoin-reaperv13_demo\reaper.conf
3a86a0088cc1e05a54c5d2708ecb2f9d  litecoin-reaperv13_demo\pthread.dll
f010428b110180e138d15e8ba1839c59  litecoin-reaperv13_demo\reaperDEMO.exe

[dishwara]

7220844fab32072fc4279436f330bb76     reaperv13_demo.zip

  File: reaperDEMO.exe
CRC-32: 4e6b6859
   MD4: abef30ed97d4f51e483b4e27fa489138
   MD5: f010428b110180e138d15e8ba1839c59
 SHA-1: 67e578532d90acef5793e41c53c74c2c8b07a662

[localhost]

7220844fab32072fc4279436f330bb76     reaperv13_demo.zip

Looks like we do have the same one... did you manage to get it working in the end?

[Fuzzy]

Reaper crashes if I run it at default worksize of 256

It runs at worksize 128, but I get the same old "Couldn't connect to server" timeout message, no matter if I'm solo or pool mining.

I should put a 1 BTC bounty on this...

[BitPorium]

not working on my 7970.....

[tacotime]

release the source code guys

In the meantime, nothing bad has happened.  The chain is alive and being hashed more than ever and it still has a lot of value.

[dishwara]

I still don't know what is in the code.

Some one has to reverse engineer it to know what it has, it may be sending some information or anything to those who need.

It works on my Win 7 , 64 bit with out any problems, but in the beginning, it gave some errors, now working at  
~226kH/s on a 5870 running at 850/1200 clk.

This is my screen. I still don't know why other cant mine.
Also its very strange that most hero members who against it not saying anything about testing or working or not working.....

[tacotime]

This is my screen. I still don't know why other cant mine.

The kernel build uses code that is specific for 58xx or 69xx GPUs... only people who own those may mine, it crashes or mines stales for everyone else.

[localhost]

The kernel build uses code that is specific for 58xx or 69xx GPUs... only people who own those may mine, it crashes or mines stales for everyone else.

I do have a 5870. It's not crashing, it just fails to connect to pool/daemon.

[grue]

I still don't know what is in the code.

Some one has to reverse engineer it to know what it has, it may be sending some information or anything to those who need.

It works on my Win 7 , 64 bit with out any problems, but in the beginning, it gave some errors, now working at  
~226kH/s on a 5870 running at 850/1200 clk.

This is my screen. I still don't know why other cant mine.
Also its very strange that most hero members who against it not saying anything about testing or working or not working.....

What's your opencl runtime/SDK version?

I'm getting this:

Code:

\|||||||||||||||||||||/
-  Reaper v13 64-bit  -
-   coded by mtrlt    -
-    DEMO VERSION     -
/|||||||||||||||||||||\

I'm now mining litecoin!
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List of platforms:
        0       ATI Stream
Using platform number 0

        0       Cypress
Binary status error code: -42
Binary loading error code: -42
Error while building from binary: -11
Program built from saved binary.
Kernel build not successful: -46
2012-03-02 21:31:49 Error: Error creating OpenCL kernel

Using Windows 7, with 2x 5850. I find it strange that it detects only 1 device, but in reality, there are 2.

[Fuzzy]

I've posted a whopping 1 BTC reward for help to figure this out.

[dishwara]

opencl/SDK  

AMD APP SDK Runtime : 2.5.793.1
AMD Display driver : 8.911.0.0000

11.11

Windows 7, 64 bit is on my pc.

May be aggression also causing problem.
I use 14 instead of 16 or 18.

[grimd34th]

I still don't know what is in the code.

Some one has to reverse engineer it to know what it has, it may be sending some information or anything to those who need.

It works on my Win 7 , 64 bit with out any problems, but in the beginning, it gave some errors, now working at  
~226kH/s on a 5870 running at 850/1200 clk.

This is my screen. I still don't know why other cant mine.
Also its very strange that most hero members who against it not saying anything about testing or working or not working.....

What's your opencl runtime/SDK version?

I'm getting this:

Code:

\|||||||||||||||||||||/
-  Reaper v13 64-bit  -
-   coded by mtrlt    -
-    DEMO VERSION     -
/|||||||||||||||||||||\

I'm now mining litecoin!
Share thread started
Share thread started
Share thread started
Share thread started
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List of platforms:
        0       ATI Stream
Using platform number 0

        0       Cypress
Binary status error code: -42
Binary loading error code: -42
Error while building from binary: -11
Program built from saved binary.
Kernel build not successful: -46
2012-03-02 21:31:49 Error: Error creating OpenCL kernel

Using Windows 7, with 2x 5850. I find it strange that it detects only 1 device, but in reality, there are 2.

http://www.microsoft.com/download/en/details.aspx?id=5555
this should fix it

[Graet]

The original purpose of Litecoin is to be a CPU coin where anybody with their computer can mine litecoins. What has happened with Bitcoin is that GPU mining on bitcoin was a lot more efficient, so a lot of people starting mining bitcoins with GPUs. This pumped up the difficulty and made CPU mining unprofitable and therefore pointless. I don't want this to happen to Litecoin and I think most people agree with me on this.

Recently, there has been some rumors that mtrlt has modified his GPU miner to work with Litecoin. And he claims to have been able to create a GPU miner that outperforms CPU miner by a lot. Of course, all this could be FUD thrown at Litecoin by Solidcoin supporters. But I have talked to mtrlt about this and he seems genuine. So I'd like to get to the bottom of this.

Here's what I'd like to accomplish:
1) Figure out if GPU mining litecoins is indeed more efficient. And if so how much better is it.
2) Do we want to switch to a new hashing algorithm that is more GPU-hostile.
3) If we do want to switch, there are a ton of other questions. Can we modify scrypt params or do we need something totally different. How far away do we do the algorithm switch? How do we get miners/pools/clients ready for the switch so that there's no downtime?

Everyone, please refrain from SolidCoin bashing in this thread. And SolidCoin supporters, please refrain from posting unless you have something constructive to say. Thanks.

any further thoughts on this?
I think it would be good to be a cpu only coin again,
tho the retards have already said they will enjoy the challenge of getting it working on gpu...

IMO Litecoin loses its point unless its CPU only

[localhost]

IMO Litecoin loses its point unless its CPU only

Clearly, yes. Now instead of being more accessible to everyone than BTC (because everyone has an okay CPU while not everyone has an okay GPU), LTC is accessible only to the few who are lucky enough to have the GPU miner working properly... Huge step backwards. The only positive effect is that it seems the BTC hashrate lowered a bit recently.

[grue]

I still don't know what is in the code.

Some one has to reverse engineer it to know what it has, it may be sending some information or anything to those who need.

It works on my Win 7 , 64 bit with out any problems, but in the beginning, it gave some errors, now working at 
~226kH/s on a 5870 running at 850/1200 clk.

This is my screen. I still don't know why other cant mine.
Also its very strange that most hero members who against it not saying anything about testing or working or not working.....

What's your opencl runtime/SDK version?

I'm getting this:

Code:

\|||||||||||||||||||||/
-  Reaper v13 64-bit  -
-   coded by mtrlt    -
-    DEMO VERSION     -
/|||||||||||||||||||||\

I'm now mining litecoin!
Share thread started
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Share thread started
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Share thread started
Share thread started
Share thread started
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Share thread started
List of platforms:
        0       ATI Stream
Using platform number 0

        0       Cypress
Binary status error code: -42
Binary loading error code: -42
Error while building from binary: -11
Program built from saved binary.
Kernel build not successful: -46
2012-03-02 21:31:49 Error: Error creating OpenCL kernel

Using Windows 7, with 2x 5850. I find it strange that it detects only 1 device, but in reality, there are 2.

http://www.microsoft.com/download/en/details.aspx?id=5555
this should fix it

already have that installed

[fivebells]

any further thoughts on this?
I think it would be good to be a cpu only coin again,
tho the retards have already said they will enjoy the challenge of getting it working on gpu...

IMO Litecoin loses its point unless its CPU only

The speedup over a CPU is less than an order of magnitude.  It's not fatal.

[ShadowAlexey]

Well, this might be interesting for NVidia GPU,couse they might perform even better than AMD.(we have to wait for sources if there will be some)
This could make system stronger, there is still no need of being afraid(increase is not so dramatical).
But it is still interesting if we will increace memory capacity to 0.5mb per core, this should make cpu faster, but they were some one saying that gpu wont suffer from it more than cpu, so it is still interesting to see the sources,because gpu memory even waving more bandwidth is still much higher latency than cpus cache, so it is interesting what is the way the kernel is made.

[dishwara]

Well, this might be interesting for NVidia GPU,couse they might perform even better than AMD.(we have to wait for sources if there will be some)

http://solidcoin.info/reaper.html
I think it works on both NVidia & AMD GPUs

[ShadowAlexey]

Well, this might be interesting for NVidia GPU,couse they might perform even better than AMD.(we have to wait for sources if there will be some)

http://solidcoin.info/reaper.html
I think it works on both NVidia & AMD GPUs

I doubt that,becouse there are precompiled kernels for 2 videochips only, both of them are AMD.

[dishwara]

Well, this might be interesting for NVidia GPU,couse they might perform even better than AMD.(we have to wait for sources if there will be some)

http://solidcoin.info/reaper.html
I think it works on both NVidia & AMD GPUs

I doubt that,becouse there are precompiled kernels for 2 videochips only, both of them are AMD.

yes

[tatsuchan]

The original purpose of Litecoin is to be a CPU coin where anybody with their computer can mine litecoins. What has happened with Bitcoin is that GPU mining on bitcoin was a lot more efficient, so a lot of people starting mining bitcoins with GPUs. This pumped up the difficulty and made CPU mining unprofitable and therefore pointless. I don't want this to happen to Litecoin and I think most people agree with me on this.

Recently, there has been some rumors that mtrlt has modified his GPU miner to work with Litecoin. And he claims to have been able to create a GPU miner that outperforms CPU miner by a lot. Of course, all this could be FUD thrown at Litecoin by Solidcoin supporters. But I have talked to mtrlt about this and he seems genuine. So I'd like to get to the bottom of this.

Here's what I'd like to accomplish:
1) Figure out if GPU mining litecoins is indeed more efficient. And if so how much better is it.
2) Do we want to switch to a new hashing algorithm that is more GPU-hostile.
3) If we do want to switch, there are a ton of other questions. Can we modify scrypt params or do we need something totally different. How far away do we do the algorithm switch? How do we get miners/pools/clients ready for the switch so that there's no downtime?

Everyone, please refrain from SolidCoin bashing in this thread. And SolidCoin supporters, please refrain from posting unless you have something constructive to say. Thanks.

any further thoughts on this?
I think it would be good to be a cpu only coin again,
tho the retards have already said they will enjoy the challenge of getting it working on gpu...

IMO Litecoin loses its point unless its CPU only

If Litecoin can be GPU mined it is best to figure out everything about that now, and either change the model of the coin to be CPU only or figure out how to compete with a GPU based Litecoin.  The "retards" are finding out more about an experimental technology we call Litecoin.  I'd personally rather all the flaws come to light NOW than in a year after I invest even more time and resources into this coin.

[localhost]

If Litecoin can be GPU mined it is best to figure out everything about that now, and either change the model of the coin to be CPU only or figure out how to compete with a GPU based Litecoin.  The "retards" are finding out more about an experimental technology we call Litecoin.  I'd personally rather all the flaws come to light NOW than in a year after I invest even more time and resources into this coin.

Ditto. Giving it a week or two to see how hashrate evolves and more reactions about this GPU mining stuff, then maybe pointing my last mining CPU to BOINC like the other ones. GPU mining = BTC, we don't need a duplicate. LTC was sold as being innovative because it was CPU-only, that isn't true anymore. This was to be expected, but I also thought the hashing algo would be updated to fight that... which doesn't seem to happen any time soon.

[Schwede65]

i have heard on btc-e chat, that mtrlt made a half-speed of the reaper13-DEMO...

the full version should work twice as fast...

so the ltc-gpu-mining is profitable down to ~0.0007 btc/ltc and not for the public with ~0.0014...

i think there must be a new ltc-algo to save the public from the grifter(s)...

Edit: the half-speed-reaper13-DEMO-release seems to be the compromise between giving the release or not

[tacotime]

i have heard on btc-e chat, that mtrlt made a half-speed of the reaper13-DEMO...

the full version should work twice as fast...

so the ltc-gpu-mining is profitable down to ~0.0007 btc/ltc and not for the public with ~0.0014...

i think there must be a new ltc-algo to save the public from the grifter(s)...

Edit: the half-speed-reaper13-DEMO-release seems to be the compromise between giving the release or not

The speeds reported by mtrlt were the same as the release for the demo, the rumor as I understood it was that his new SC2 miner was supposed to be twice as fast for GPU

I've wondered if the reason mtrlt has not released the source code is because it may borrow heavily from ssvb's code, as ssvb was the one to solve the in-place hashing of ltc

Anyway, this outlines the difficulty in actually a creating an algorithm that can not easily be serialized so that it will run faster on a CPU than a GPU.  I've been thinking about it some, and I've wondered if using multiple algorithms and randomizing a number of the settings for each (then possibly the order in which they are used) to generate 10s or hundreds of thousands of possible algorithms, only one of which could possibly decrypt the next block.  The difficulty in parallelizing the data would have to do with the difficulty of assembling a large number of algorithms sequentially and then assessing them.  It's hard to think of something that a CPU can due better than a GPU when it's a repetitive task based on the same operations of a dataset...  Having to brute force the actual construction of the algorithm may be something that a GPU might struggle with, though.

edit: There's a pretty neat paper of algorithms and their runtime comparisons for GPU/CPU.  There are sorting and physics algorithms that perform significantly slower on a CPU as compared to a GPU.

www.cs.utexas.edu/users/ckkim/papers/isca10_ckkim.pdf

More info on the mentioned sorting algorithm:

Our 4-core implementation is competitive with the per-
formance on any of the other modern architectures, even
though Cell/GPU architectures have at least 2X more
compute power and bandwidth. Our performance is
1.6X–4X faster than Cell architecture and 1.7X–2X faster
than the latest Nvidia GPUs (8800 GTX and
Quadro FX 5600).

Also note that as the set size becomes larger, GPUs run out of memory and are unable to even compute the set, although extrapolating from the data even if they were able to it would still be slower than for the CPU.
http://pcl.intel-research.net/publications/sorting_vldb08.pdf

The algorithm was subsequently surpassed with this GPU one, however for small data sets Intel's TBB parallel sort is still faster.
http://mgarland.org/files/papers/gpusort-ipdps09.pdf
Apparently over the past few years there has been a battle between Intel and nVidia to try to find things that CPUs and GPUs do better than one another, and there is a wealth of well-cited literature out there.

The algorithm was again overhauled, and CPU-based radix/merge sort still manages to beat out GPUs in a number of cases:

Comparing CPUs and GPUs: In terms of absolute performance
of CPU versus GPU, we find that the best radix sort, the CPU radix
sort outperforms the best GPU sort by about 20%. The primary rea-
son is that scalar buffer code performs badly on the GPU. This ne-
cessitates a move to the split code that has many more instructions
than the buffer code. This is enough to overcome the 3X higher
compute flops available on the GPU4 . On the other hand, the GPU
merge sort does perform slightly better than the CPU merge sort,
but the difference is still small. The difference is due to the absence
of a single instruction scatter, and the additional overheads, such as
index computations, affecting GPU performance.

http://dl.acm.org/citation.cfm?id=1807207

So, it seems reasonable that an algorithm which is heavily dependent on the radix sort implemented will perform faster on CPUs as compared to GPUs.  It's important that only non-multifield data be used, because a very fast GPU algorithm was implemented for that recently:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5713164

There's also a tree search algorithm here which runs significantly faster with smaller data sets on CPUs/MICA versus GPUs; if it could be integrated into an encryption algorithm it might destroy GPU performance

www.webislands.net/pubs/FAST__SIGMOD10.pdf

[throwaway]

The original purpose of Litecoin is to be a CPU coin where anybody with their computer can mine litecoins. What has happened with Bitcoin is that GPU mining on bitcoin was a lot more efficient, so a lot of people starting mining bitcoins with GPUs. This pumped up the difficulty and made CPU mining unprofitable and therefore pointless. I don't want this to happen to Litecoin and I think most people agree with me on this.

Recently, there has been some rumors that mtrlt has modified his GPU miner to work with Litecoin. And he claims to have been able to create a GPU miner that outperforms CPU miner by a lot. Of course, all this could be FUD thrown at Litecoin by Solidcoin supporters. But I have talked to mtrlt about this and he seems genuine. So I'd like to get to the bottom of this.

Here's what I'd like to accomplish:
1) Figure out if GPU mining litecoins is indeed more efficient. And if so how much better is it.
2) Do we want to switch to a new hashing algorithm that is more GPU-hostile.
3) If we do want to switch, there are a ton of other questions. Can we modify scrypt params or do we need something totally different. How far away do we do the algorithm switch? How do we get miners/pools/clients ready for the switch so that there's no downtime?

Everyone, please refrain from SolidCoin bashing in this thread. And SolidCoin supporters, please refrain from posting unless you have something constructive to say. Thanks.

coblee,

Given that:

* in a couple of years every (consumer) CPU sold will have opencl-capable integrated graphics
* bitcoin mining will move more and more towards FPGAs/ASICs

I don't think any changes are necessary. Very soon anybody will have a computer capable of GPU-mining Litecoin. Also, since eventually people will stop using GPUs to mine bitcoin, the swings in difficulty from people switching between the two chains won't be a problem.

[da2ce7]

I don't think any changes are necessary. Very soon anybody will have a computer capable of GPU-mining Litecoin. Also, since eventually people will stop using GPUs to mine bitcoin, the swings in difficulty from people switching between the two chains won't be a problem.

Yes, don’t threat.  GPU's are at most 10x faster than cpu's for litecoin mining.  For Bitcoin it is at least 100x faster on a GPU.

This means that Litecoin is at least 10x more efficient on a CPU than Bitcoin.

Over time, this gap will narrow; as the in-built GPU's in inside every computer get better.

[m3ta]

Yes, don’t threat.  GPU's are at most 10x faster than cpu's for litecoin mining.  For Bitcoin it is at least 100x faster on a GPU.

Over time, this gap will narrow; as the in-built GPU's in inside every computer get better.

http://scottbush.net/language/apostrophes-have-no-place-in-plural-acronyms/

Just sayin'.

[Cosbycoin]

Wouldn't changing the algorithm force a new blockchain for litecoin? That'd screw up every pool, exchange, client, etc. which is probably going to annoy a lot of the network.
And if that did cause some sort-of "litecoin 2", that would send the value of litecoin downhill, meaning anyone who currently has a lot of their money in litecoins, ends up with nothing...

Coblee has multiple options.

1) Drop support for litecoin1 and start litecoin2 or whatever, and give people all the existing coins in Litecoin1 into Litecoin2 (I did this with SolidCoin v2). Of course this also means the guys GPU mining still have their new coins in the new network but it potentially means you can start fresh with a new algorithm. It's a lot of work however.

2) Do a forking change in litecoin itself. The problem with this is the "old network" will continue in parallel with the "new litecoin". Which leads to a lot of support issues "Which litecoin are you on?".

3) Start an entirely new coin. Like he did with Litecoin over fairbrix. Probably the second easiest option to pull off since you don't have to support multiple old things and allows him to do some things from scratch a bit better. However the downside is the original Litecoins probably decrease in value due to no more developer (like tenebrix and fairbrix).

4) Do nothing. The easiest option.

The hardest thing is, unless you are well versed in understanding CPU and GPU architecture making a CPU hard coin is very difficult. Given Coblees failure to know if Scrypt was GPU hard are we going to believe he can now make one that is? This will require a lot of work and a lot of testing to verify. And you're going to need talented C++ and OpenCL coders to help you out I think.

So far it looks like LTC is doing just fine. 

[str4wm4n]

Yes, don’t threat.  GPU's are at most 10x faster than cpu's for litecoin mining.  For Bitcoin it is at least 100x faster on a GPU.

Over time, this gap will narrow; as the in-built GPU's in inside every computer get better.

http://scottbush.net/language/apostrophes-have-no-place-in-plural-acronyms/

Just sayin'.

DISREGARD GRAMMERS

AWQUIRE LITECOINZ

[vmarchuk]

Anyone know what proper setting for 7xxx series card using reaper for litecoin ?

My 7xxx card get half speed of 6xxx series cards. Using 12.2pre.

When I put aggression higher than 12, I get many GPU error on 7xxx card at half hash rate 6xxx, but on 6xxx card, I can set aggression near 22 before 6xxx give me gpu error.

I get near 450KhashS on 6970 but only near 225KhashS on 7950 before GPU error.

[Bitinvestor]

Anyone know what proper setting for 7xxx series card using reaper for litecoin ?

My 7xxx card get half speed of 6xxx series cards. Using 12.2pre.

When I put aggression higher than 12, I get many GPU error on 7xxx card at half hash rate 6xxx, but on 6xxx card, I can set aggression near 22 before 6xxx give me gpu error.

I get near 450KhashS on 6970 but only near 225KhashS on 7950 before GPU error.

That's as good as it gets at the moment. Reaper is not yet optimized for the 7xxx series.

[Cosbycoin]

Anyone know what proper setting for 7xxx series card using reaper for litecoin ?

My 7xxx card get half speed of 6xxx series cards. Using 12.2pre.

When I put aggression higher than 12, I get many GPU error on 7xxx card at half hash rate 6xxx, but on 6xxx card, I can set aggression near 22 before 6xxx give me gpu error.

I get near 450KhashS on 6970 but only near 225KhashS on 7950 before GPU error.

That's as good as it gets at the moment. Reaper is not yet optimized for the 7xxx series.

This statement alone implies that the future hash rate of the LTC network will get larger.

[AnonyMint]

Click the following link for details:

https://bitcointalk.org/index.php?topic=45849.msg2940005#msg2940005

Something I've wondered:

Why are you using N=1024, r=1, and p=1 for scrypt?  Why didn't the recommended values from the paper, N=1024, r=8, p=1 get used?

If I remember correctly, ArtForz said that the parameters (1024, 1, 1) resulted in a lower GPU/CPU performance ratio.
Some analysis by him can be found here: https://bitcointalk.org/index.php?topic=45849.0

I have addressed this point in my link above.

From what I know of the gpu miner, option 3 of modifying the scrypt parameter will have minimal impact. The pad size did not seem to matter much, and can be compressed for lack of a better word, with on the fly value reconstruction. So any increase in pad size will have a relatively equal impact on cpu miners until you exceed their cache size, at which point, gpus may become even more efficient.

I think you will be stuck with option 2, finding a completely different hashing algorithm.

Until you put an Scrypt inside of an Scrypt, such that the inner stays in the cache.  See my link above.

Are you saying he has disproved the sequential memory hardness for the ROMix algorithm from the original scrypt paper?

No, apparently the issue is the relative memory bandwidths of the different features of hardware (and the ability to hide memory latency in multitheading) and the original Scrypt sequential memory hard proof doesn't factor that. My link above proposes a way to elevate the CPU's cache to a large memory size to overcome the discrepancy.

Anyway, this outlines the difficulty in actually a creating an algorithm that can not easily be serialized so that it will run faster on a CPU than a GPU.

See my link above for an idea for the algorithm.

well without decent network hashrate it can be attacked easy by any botnet ...

See my link above for another idea of how to eliminate botnets with a CPU-only coin.

any further thoughts on this?
I think it would be good to be a cpu only coin again,
tho the retards have already said they will enjoy the challenge of getting it working on gpu...

IMO Litecoin loses its point unless its CPU only

The speedup over a CPU is less than an order of magnitude.  It's not fatal.

Appears to be greater than an order-of-magnitude. See my link above.

2)
I suppose that increasing the memory size parameter of scrypt to a very large amount (megabytes...) which doesn't fit in the cache would mean that it'd be infeasible to do hash attempts in parallel with a GPU (and maybe even with several CPU cores), but it also most likely means that people couldn't use their computer to do other stuff while mining litecoins due to system responsiveness issues. Therefore it's possible that the current scrypt parameters as chosen by ArtForz and Lolcust are the best, espeically if bitcoin GPU mining remains more profitable than litecoin GPU mining.

Either the CPU is compute-bound (in small cache memory) or memory-bound in large memory. Either way you can't use your computer for other work that requires the same bound if you want to get maximum hashing rate.

IMO Litecoin loses its point unless its CPU only

Clearly, yes. Now instead of being more accessible to everyone than BTC (because everyone has an okay CPU while not everyone has an okay GPU), LTC is accessible only to the few who are lucky enough to have the GPU miner working properly... Huge step backwards. The only positive effect is that it seems the BTC hashrate lowered a bit recently.

I became interested in mining a second cryptocurrency only because tennebrix (and then others) came up with a way to make CPU mining viable again... I figured, why not put the two or three decent machines I run at home, as well as a couple strays at my shop, onto a useful task instead of simply letting them sit around growing slowly more obsolete by the day?  I suspect I represent a fairly typical LTC/SC enthusiast, in that regard.

Put bluntly, if GPU mining becomes viable for LTC and/or SC, their entire raison d'etre vanishes.

Since I was asked to clarify, "significantly more efficient", I guess I will post some hash per watt numbers.

According to litecoin wiki mining hardware comparison, an AMD Phenom X4 955 at 3.6ghz gets 24kh @ 125 watts. This translates to 0.192kh per watt.
A gpu rig consisting of 69xx series gpus can produce 998kh @ 920 watts at the wall. This translates to 1.08kh per watt.

So does at least a 5.6 factor increase in *efficiency* qualify as "significantly more"?

Consider the litecoin wiki entry for the Intel Core i7 860 which produces 25kh at 153 watts (a believable wattage consumption for the entire system). It gives a system kh/watt score of only 0.163. The gpu example is now a factor of 6.6 times more efficient.

PS, Mtrlt has gotten better kh/watt scores by playing with the clocks and voltages, but I figured I would give you an initial test result.

More hardware comparisons for Litecoin:

http://litecoin.info/Mining_Hardware_Comparison
http://coinpolice.com/gpu/

coblee,

Given that:

* in a couple of years every (consumer) CPU sold will have opencl-capable integrated graphics
* bitcoin mining will move more and more towards FPGAs/ASICs

I don't think any changes are necessary. Very soon anybody will have a computer capable of GPU-mining Litecoin. Also, since eventually people will stop using GPUs to mine bitcoin, the swings in difficulty from people switching between the two chains won't be a problem.

As far as I can see, the consumer-grade GPU on the CPU motherboard won't be the threat that exists for the stand-alone cards which will always have order-of-magnitude greater large memory bandwidth, unless the motherboard becomes something of an amalgamation with only GDDR5 memory, e.g. the Sony PS4 (see link with the post that I linked at top of this post of mine). If and when that ever become ubiquitous, then the CPU-only coin will still be mined competitively by the amalgamated system.

One thing (somewhat theoretical) I would throw out there is that as GPUs become more "CPU like" they will devote the necessary resources (transistors and chip yield) to increased L1 cache.  GPU long since outstripped the growth in pixel counts so they devoted more resources to improved image quality at a fixed number of pixels and/or polygons.  The GPU resources are growing faster than developers ability to use them as devising more complex and realistic "effects" requires more human capital than simply doubling the polygon count or going from a 800x600 pixel count to 1920x1200 pixel count.  So it will be increases in GPGPU workload which increasingly drives development of future GPUs.

Given my idea of nested Scrypt, if the GPU has adequate L1 cache per CU, the problem remains that if I set the parameters to be for example 4 cores running 32KB inner scrypt, with 1.5GB outer scrypt, then CPU (with 6GB GDDR RAM) can only employ 4 of its CU (cores). So it can only use a fraction of its hardware.

For example, the HD 7970 has 32 CU (cores) each with 16 KB L1 cache and 24 KB L2 cache running at 2TB/s and 0.7 TB/s respectively. But the Intel Haswell Core i7/i5 has 4 cores with 32 KB L1 cache and 256 KB L2 cache running at 1TB/s and 0.33 TB/s respectively.

So if the coin requires 32 KB inner Scrypt, then HD 7970 is going to be at the 0.25 to 0.5 TB/s of the GDDR RAM but with much latency and only 4 threads so much slower than the CPU. Even if the coin requires only 16 KB inner Scrypt or later version of the GPU has 32 KB L1 cache, the GPU is still going to be employing only 4 threads same as for the CPU, but may run at twice the speed of the CPU because of the double L1 cache speed.

GPU traditionally had very little local cache because there is no need when performing traditional graphics work.  That dynamic likely won't hold true in the future.  NVidia Tesla cards for example can be configured to double the amount of L1 cache because it is so useful in boosting performance of some GPGPU functionality.   Larger L1 caches will eventually trickle down into consumer grade products to.

My other idea is to force the total memory requirement of the outer Scrypt higher than any GPU, since I know of no GPU which allows addon GDDR memory. There is no retail market for GDDR memory.

No coin today is "anti-GPU" it is they can be described as "large L1 cache dependent".

Not "today", but my idea is the nested Scrypt idea should make them more "anti-GPU" when coupled with a large L1 or L2 cache dependent.

Employing the 256 KB L2 cache of the Intel Core family would mean the HD 7970 can only run three threads and still be in L2 cache but its L2 cache is 2X faster than the CPU, so 2 x 3/4 = 3/2 speed of the CPU. Or the HD 7970 could run 4 threads being main memory bound which has comparable bandwidth but memory latency would accumulate, so slower than the CPU.

SolidCoin's Hashing Algorithm

Actually the SolidCoin hash was developed to be fairly equal in performance on GPUs and CPUs, watt for watt. It is currently delivering that and has been for some time (with a small favor to CPUs). SolidCoin takes all consumer hardware that is viable so we can let the widest range of people mine it fairly. Unlike Bitcoin which is going to be FPGA soon and Litecoin (which was supposed to be CPU only and is now a GPU coin), we want everyone to be able to mine.

What looks interesting is that they still claim the SC2 algorithm to be GPU-resistant. I'm not at all convinced. Any technical opinion on this?

It's not GPU resistant, but random reads on constant 4MB buffer make the difference of CPU/GPU slightly lower cause GPU lucks on a lot of cache. But it's still 4-6 times faster on GPU as on CPU

Check out SolidCoins mining page for info on how a correct implementation of CPU/GPU hard algorithm should figure in performance.
http://wiki.solidcoin.info/wiki/Mining_Hardware_Performance

I see nothing correct in your Hashing Algorithm, i've implemented 2.5 faster Version of miner for it (CPU) and due lack of time and profit for mining there is even 3x-8x better implementation of GPU miner for Solidcoin so it's nothing other

That SolidCoin link shows roughly the same advantage for the AMD GPU HD 7970 over the Intel CPU iCore as for Litecoin.

I didn't take the time to study the linked SolidCoin hashing algorithm, but if it is based on a claimed advantage of randomized memory latency, note the point I make in my link at the top, is that this latency can be hidden by the multithreading of many threads.

[AnonyMint]

Elaboration:

https://bitcointalk.org/index.php?topic=267522.msg2955080#msg2955080