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Other => CPU/GPU Bitcoin mining hardware => Topic started by: robmon on January 04, 2011, 06:05:25 PM



Title: Building computer for mining
Post by: robmon on January 04, 2011, 06:05:25 PM
Hi,

I have recently found Bitcoin (via Max Keiser) and really believe this is the way to go! :-)

I have a crappy computer with an old grapics card and i'm thinking of building a dedicated GPU miner. How would you build a computer that is only to be used for mining bitcoins and nothing else? Is it as simple as getting a computer with one of the more expensive (consumer) graphic cards and jam in fast RAM and disk and off we go?

 ???


Title: Re: Building computer for mining
Post by: jimbobway on January 04, 2011, 06:25:01 PM
How much are you willing to spend?  You should look into pooled mining.  http://mining.bitcoin.cz/

The best way to obtain bitcoins, in my opinion, is to buy them.


Title: Re: Building computer for mining
Post by: Akilae on January 04, 2011, 06:36:57 PM
Essentially its that simple. To make it efficient, you want the best MHash/Watt and MHash/$, since the power draw on a mining setup essentially nulls the profits unless you're running a big Radeon card with high ratios.


From the time I've spent lurking on the forums, and the sources posted herein, I think the general way you want to go regardless of budget is:

-Maximum ATI gfx card, even multiples that aren't running in Crossfire. (For separate device id's for separate instances of GPU miners)
..... For some reason, ATI cards are several multiples faster than nVidia for mining for the price. An $80 radeon 5570 gets slightly more khashes/s than my $200 gtx460.
..... I'm unsure of the effects of mining with 2 cheap Radeon's non crossfire versus 1 fancy Radeon by itself. It may be mostly additive.

-Cheap CPU, unless you also want it to mine at the same time, then maximize it within your budget. GFX takes MAJOR priority however. More cores are better than faster cores. An AMD X6 or a newfangled intel i7 are ideal for maximum cores, but get expensive. Again, go AMD if price is a concern, they're plenty fast and 20-30% cheaper. GPU miner programs have minimal CPU impact.

-Minimal RAM, 2-4GB, depending on OS. This is just to have a responsive overall system. Bitcoin while generating on 4 of my 4 cpu cores uses ~28 MB of RAM.

-Minimal hard-disk. Doesn't need to be super fast or even big. Has the OS and your miners.

-High Airflow Case. A necessity since you'll likely be overclocking whatever you use. If price isn't an issue, get an aftermarket CPU cooler or water cooler. Even if you don't mess with CPU OC's, GPU OC'ing is quick and easy and generates a lot of heat. Antec's 300/600/900/1200 cases are loved by everyone, are inexpensive, and are regarded as among the best air cooling towers you can get.

-As efficient a PSU as possible. Probably with some decent wattage headroom for upgrades down the line as the hashing difficulty factor increases.

-Minimal Motherboard, unless you really wanna do a CPU OC. Make sure it accepts PCIe 2.0 x16, two of those slots if you want to run multiple cards (crossfire ready, etc), and the variety/quantity of RAM you want.

Valuable Resources:
http://golubev.com/gpuest.htm
http://pastebin.com/AvymGnMJ
http://www.bitcoin.org/wiki/doku.php?id=bitcoin_miners


Title: Re: Building computer for mining
Post by: Cryptoman on January 04, 2011, 07:11:04 PM
If you're in the U.S., you can get a Sapphire Radeon HD 5770 from Amazon for $99 after rebates (until 2011.1.15).  I think this is the best hash/$ deal currently out there.


Title: Re: Building computer for mining
Post by: Sawzall on January 04, 2011, 09:51:32 PM
Buying hardware and power for mining is not going to be profitable. Best way is to use a machine you already have and power you don't pay for.
If I'm actually wrong and there is a way to turn a profit with purpose-bought hardware, I'd love to know about it.


Title: Re: Building computer for mining
Post by: Hal on January 04, 2011, 11:27:38 PM
According to https://en.bitcoin.it/wiki/Mining_Hardware_Comparison (https://en.bitcoin.it/wiki/Mining_Hardware_Comparison), the 5770 draws about 100W and generates 150 Mhash/s. According to http://www.alloscomp.com/bitcoin/calculator.php (http://www.alloscomp.com/bitcoin/calculator.php), this should generate a block every 5 days. 5 days is 120 hours, times 100W is 12 kWh. Around here it's $0.20 per kWh, so that's about $2.50 per block for electricity. A block of 50 bitcoins is worth about $15 now, less $2.50 is $12.50 profit. The $99 card will be paid off after 8 blocks, so that's about 40 days at current difficulty. After that it's pure profit.

Most people assume difficulty will continue to rise, but I think it will level off soon, because except for unusual deals like this one, GPU mining is close to becoming unprofitable.


Title: Re: Building computer for mining
Post by: lach on January 05, 2011, 05:12:31 AM
Im running a miner on my laptop with an ATI 5650 mobile. Gets roughly 48Mhash. if the TDP on wikipedia of 19W is accurate then these mobile chips give pretty good Mhash/W. Would be good if they put them on PCIe boards for a desktop


Title: Re: Building computer for mining
Post by: Akilae on January 05, 2011, 05:39:43 AM
While the mobile cards would be great for MHash/watt, it would probably not be very much so on Mhash/$, thanks to the price barrier of miniaturization.
If looking at the long term, as long as difficulty rate doesn't change toooo quickly, it may be worth the investment.

As it stands now, you can get an asus g73 (i think) for like $1300, which has a mobile radeon 5870... Matter of fact I nearly got that laptop for going back to the spring semester at university, but built my current desktop instead for an equal price. (Which the desktop turned out to be multiples more powerful in other ways, just apparently not bitcoin mining. EX: COMSOL or Solidworks simulations... ugh.)

I'm kindof on the fence about whether the increased investment (Which isn't so bad when you take into account the fact that a laptop is its own entire system, not "just" one super expensive component.) would be worth the decreased power draw. It may in the long run, but I suppose mileage may vary.

Alternatively, a gtx480m laptop:
Note that the listed power draw is 180W for the ENTIRE laptop, while the gtx480m is said to be almost identical to a desktop gtx465 in performance.
http://www.tomshardware.com/reviews/geforce-gtx-480m-w880cu-avadirect,2679.html


Title: Re: Building computer for mining
Post by: teknohog on January 05, 2011, 01:46:47 PM
While the mobile cards would be great for MHash/watt, it would probably not be very much so on Mhash/$, thanks to the price barrier of miniaturization.

It would be great to have "mobile" GPUs in standard PCIe cards. I would definitely pay extra to get that improved performance per watt. I have already been using Mini-ITX/DTX machines for years, with "mobile" CPUs and chipsets in "desktop" systems.

One problem with using laptops for full-time number crunching is that the size necessitates small and noisy fans. Having those "mobile" components in an ATX case is pretty nice, since you can then have huge heatsinks and a large, slow fan. The only thing missing is a strong "mobile" GPU.


Title: Re: Building computer for mining
Post by: fabianhjr on January 06, 2011, 04:09:17 PM
Ok

Mobo
Get one with 4x 16xPICe rails. All those 16xPCIe rails must have another rail in between EDIT: or a space at least. CPUs don't compare with GPUs for mining. If it says it can do 4-way CrossFire or SLI you are good to go. :-)
http://brazil.test.giga-byte.com/FileList/Image/mb_overview_4way-vga.jpg

Examples
Intel
Gigabyte UD9(GA-X58A-UD9)
Asus Rampage III
Asus P6T7 Supercomputer
EVGA Classified 4-Way SLI
AMD
MSI 790FX-GD70
..dunno of any more, can anyone help?

Graphics Card
There is only one option really, the ATI Radeon HD 5970, it gets you around 550 MHashes/sec.(Sorry, can't tell for sure. I got a 5870 and I get around 300MHashes/sec) They cost like 600 dollars each and you could be doing 600 MHashes/sec easily By OCing the GPU and UCing the memory. Which means it will cost you around 1 USD per MHash/sec + electric bill of it running. Also if you plan to get more than 2 in the 4-way mobo then the liquid cooling upgrade is mandatory.

Cooling
I suggest you get the Koolance block for the 5970. Refer to this review please: http://www.youtube.com/watch?v=7HfXEA2EJpI (http://www.youtube.com/watch?v=7HfXEA2EJpI)

PSU
Get the biggest one you can get.(1500 Watts) Corsair has a big reputation for its reliability.

Case
Make sure you have at least 8 slots in the back for the GFX.

CPU and RAM
Get an economic one since the GPUs will be doing the job. Same goes for RAM.

Operating System
I heard that Windows has a limitation of 4 GPUs(You will have a max of 8 per rig) so I suggest you use a Linux distro such as Debian or Arch Linux.

I hope it helps. :)


Title: Re: Building computer for mining
Post by: WSDN on January 07, 2011, 01:58:18 AM
exellnet @fabianhjr  and the total price is? :P i preffer buy bitcoins with this money!


Title: Re: Building computer for mining
Post by: fabianhjr on January 07, 2011, 02:44:30 AM
You would have _the_ 20 TFLOPs computer though. This should be a 15 hundred 3K build depending on your choices.(Also with cooling it should get to at least 25 TFLOPS) which would mean you are paying 1 USD per 10 GFLOPS. Buy 40 of this and you get yourself a 1 PFLOPS cluster which would be max about 120K. If you do so you would account for half the current processing power in the Bitcoin network today or so. If you ask me this is a powerful build. I estimate the hashrate of 40 of this at around 100 GHashes/sec. That is enough to generate on average every 11 minutes.


Title: Re: Building computer for mining
Post by: The Script on January 24, 2011, 01:23:21 AM

What about someone who doesn't want to spend a lot of money on building a super mining computer but still wants to be able to generate a few bitcoins now and again through pooled mining?  All I have right now is my Lenovo Thinkpad which generates ~ 1800 khash/s when running the bitcoin program and only ~800 khash/s when running a miner connected to Slush's server.  Running the miner for two days straight generate me about 30 mBTC, which is far from exciting.  My thought was to find some old towers, install Ubuntu on them, download the miner and then connect them to the mining pool.  If I could get a couple free towers then I'd just use their CPUs and hopefully several of them would bring my total hash rate up to a point where I could get rewarded more. 

Are there any options you guys know of other then forking out a bunch of cash for expensive graphics cards?


Title: Re: Building computer for mining
Post by: ElectricGoat on January 24, 2011, 01:26:22 AM
According to Ryo's paper, your old towers will not be profitable if you pay for electricity.


Title: Re: Building computer for mining
Post by: The Script on January 24, 2011, 02:20:02 AM
According to Ryo's paper, your old towers will not be profitable if you pay for electricity.

I don't pay for electricity.  I'm just wondering if I should invest in getting a graphics card or whether that will pay off in the long run.  I've been offered several free towers by some friends already, but the problem is connecting them to the internet.  At the place I rent all we have is Wii-Fii so I would need wii-fii cards for each tower.  The other option would be to set them up at school (where I also don't have to pay for electricity) but I'm not sure of the legal implications of that yet.  :P  It might be regarded as a "money-making" venture and therefore not allowed on school property.

From what I've read on this forum one decent graphics card is worth many, many CPUs as far as processing power goes.



Title: Re: Building computer for mining
Post by: ElectricGoat on January 24, 2011, 06:27:47 AM
My crappy GPU, installed by default on my $500 computer, is as fast as a dozen old pentium 4's.


Title: Re: Building computer for mining
Post by: grondilu on January 24, 2011, 07:53:54 AM
The best way to obtain bitcoins, in my opinion, is to buy them.

I think that too but we should not discourage people for mining.  The more miners there are, the stronger is the network.


Title: Re: Building computer for mining
Post by: The Script on January 24, 2011, 07:55:17 AM
Hmm, since my wife would kill me if I set up a CPU farm of several dozen computers in our house, perhaps I should go the route of a single miner with a reasonably powerful GPU.   :P

(Also the landlord would probably start wondering I was growing marijuana when he noticed the electric bill.)   :D


Title: Re: Building computer for mining
Post by: The Script on January 24, 2011, 07:57:21 AM
The best way to obtain bitcoins, in my opinion, is to buy them.

I think that too but we should not discourage people for mining.  The more miners there are, the stronger is the network.


You guys are doubtless correct, and I plan on purchasing bitcoins at some point soon, but there is an addictive adventure side to the mining process.  It's like the gold fever of the California gold rush.  :P



Title: Re: Building computer for mining
Post by: ribuck on January 24, 2011, 10:38:53 AM
... there is an addictive adventure side to the mining process

There's that "rush" when you use the computer in the morning and you see that it says "Generated: +50.00". There's also that "downer" when you have gone weeks without generating.


Title: Re: Building computer for mining
Post by: Cdecker on January 24, 2011, 10:59:29 AM
The best way to obtain bitcoins, in my opinion, is to buy them.

I think that too but we should not discourage people for mining.  The more miners there are, the stronger is the network.

To be more correct: the more independent miners there are the stronger the network, pools still are a single point of failure :D


Title: Re: Building computer for mining
Post by: The Script on January 24, 2011, 11:32:30 AM
The incentive for independent miners seems to be quickly decreasing, because the average person can't just download bitcoin, fire up his computer and expect to generate any coins in a reasonable period of time.  So it seems like the tendency will be towards group mining or people just won't bother to run the application. 


Title: Re: Building computer for mining
Post by: Nefario on January 24, 2011, 01:37:54 PM
The incentive for independent miners seems to be quickly decreasing, because the average person can't just download bitcoin, fire up his computer and expect to generate any coins in a reasonable period of time.  So it seems like the tendency will be towards group mining or people just won't bother to run the application. 

Specialisation of labour. Should I say more?


Title: Re: Building computer for mining
Post by: The Script on January 24, 2011, 07:23:28 PM
The incentive for independent miners seems to be quickly decreasing, because the average person can't just download bitcoin, fire up his computer and expect to generate any coins in a reasonable period of time.  So it seems like the tendency will be towards group mining or people just won't bother to run the application. 

Specialisation of labour. Should I say more?

I just thought the idea was that the more people running the bitcoin client, the stronger the network.  If only 30 people with specialized high-power mining setups are doing all the mining (and several mining pools) then you'll have a less secure network as there will be far fewer points of failure, right?  I'm not trying to be the newbie who thinks he found the crack in bitcoin's armour.  This is probably a non-issue as enough people will keep mining even for diminished returns on bitcoins, and additionally some will runt the client to support the network even without expecting to gain any bitcoins from it.  Thoughts?


Title: Re: Building computer for mining
Post by: FatherMcGruder on January 24, 2011, 07:43:35 PM
I just thought the idea was that the more people running the bitcoin client, the stronger the network.  If only 30 people with specialized high-power mining setups are doing all the mining (and several mining pools) then you'll have a less secure network as there will be far fewer points of failure, right?  I'm not trying to be the newbie who thinks he found the crack in bitcoin's armour.  This is probably a non-issue as enough people will keep mining even for diminished returns on bitcoins, and additionally some will runt the client to support the network even without expecting to gain any bitcoins from it.  Thoughts?
People will also run the client for the sake of collecting transaction fees.


Title: Re: Building computer for mining
Post by: ribuck on January 24, 2011, 08:07:18 PM
At some point, the standard client might detect and support graphics cards "out of the box". It's unlikely to happen soon, of course.


Title: Re: Building computer for mining
Post by: The Script on January 24, 2011, 11:35:30 PM
I just thought the idea was that the more people running the bitcoin client, the stronger the network.  If only 30 people with specialized high-power mining setups are doing all the mining (and several mining pools) then you'll have a less secure network as there will be far fewer points of failure, right?  I'm not trying to be the newbie who thinks he found the crack in bitcoin's armour.  This is probably a non-issue as enough people will keep mining even for diminished returns on bitcoins, and additionally some will runt the client to support the network even without expecting to gain any bitcoins from it.  Thoughts?
People will also run the client for the sake of collecting transaction fees.

Perhaps I don't understand the system completely (highly likely).  Do you have to be generating coins to be part of the network, or do you simply have to have the client running on your computer?  I thought generating the coins was how individuals supported the network by verifying previous bitcoin transactions. 



Title: Re: Building computer for mining
Post by: FatherMcGruder on January 25, 2011, 12:08:20 AM
Perhaps I don't understand the system completely (highly likely).  Do you have to be generating coins to be part of the network, or do you simply have to have the client running on your computer?  I thought generating the coins was how individuals supported the network by verifying previous bitcoin transactions. 
I think you also collect the transaction fees associated with those transactions, meaning that you have to have the client set to generating coins. Can someone confirm? Come to think of it, that doesn't solve the problem of having minuscule processing power compared to the rest of the network, since there's just as much competition for the fees as the regular awards per block. I suppose the incentive to "generate coins" will have to come from the desire to win the lottery by solving a block, and that depends on the value of bitcoins increasing dramatically.


Title: Re: Building computer for mining
Post by: The Script on January 25, 2011, 12:58:22 AM
Perhaps I don't understand the system completely (highly likely).  Do you have to be generating coins to be part of the network, or do you simply have to have the client running on your computer?  I thought generating the coins was how individuals supported the network by verifying previous bitcoin transactions. 
I think you also collect the transaction fees associated with those transactions, meaning that you have to have the client set to generating coins. Can someone confirm? Come to think of it, that doesn't solve the problem of having minuscule processing power compared to the rest of the network, since there's just as much competition for the fees as the regular awards per block. I suppose the incentive to "generate coins" will have to come from the desire to win the lottery by solving a block, and that depends on the value of bitcoins increasing dramatically.
[/quote

Ah, I get what you are saying.  But transaction fees are few and far between, from what I can tell, and as you said have the same difficulty associated as solving blocks.  But I suppose as the difficulty increases people will stop mining, causing the difficulty to decrease, combined with the rising value of bitcoins which will bring some people back to mining. 


Title: Re: Building computer for mining
Post by: Cryptoman on January 25, 2011, 02:19:57 AM
One thing to keep in mind is that the reward for crunching a block gets cut in half each 210,000 blocks.  If the transaction fees don't start going up at least a little, there may be little incentive to mine/generate in the future.


Title: Re: Building computer for mining
Post by: ribuck on January 25, 2011, 11:54:10 AM
If the transaction fees don't start going up at least a little, there may be little incentive to mine/generate in the future.

It's the miners who set the fees, so this is a self-correcting "problem".


Title: Re: Building computer for mining
Post by: The Script on January 25, 2011, 06:43:16 PM

This bothers me.  I thought one of the main advantages of bitcoins was that you didn't have to deal with transaction fees.  What sort of safeguards are in place to prevent transaction fees from becoming prohibitively high?  From bitcoinme.com:

"Whereas credit cards and other online payment systems typically cost 1-5% per transaction, plus various other fees adding up to hundreds of dollars...  Bitcoin usage and transactions are always free.  It doesn't matter if you send $0.01... or $1,000,000.00...  the transaction cost is always the same:  free"

Is this blatantly false?  If so you shouldn't be advertising to people that the transactions are always free.  Can someone explain to me how this works? 


Title: Re: Building computer for mining
Post by: theymos on January 25, 2011, 07:26:28 PM
As far as I understand current bitcoind implementation does not have an easy way to force non-zero fee (which is a good thing).

The relevant code is very easy to change. ArtForz used to operate with non-standard, less-restrictive fee rules.

Is this blatantly false?

Yes. Bruce "exaggerates" a lot. There is also no encryption in Bitcoin, payments are not guaranteed to be irreversible (though reversal is difficult), and anonymity is not great.

Quote
What sort of safeguards are in place to prevent transaction fees from becoming prohibitively high?

The small-fee transactions will accumulate, which will incentivize new miners to step in and claim those fees. The required fee should always be quite small, though these transactions may take a while to be included.


Title: Re: Building computer for mining
Post by: grondilu on January 25, 2011, 07:43:20 PM
What sort of safeguards are in place to prevent transaction fees from becoming prohibitively high? 

Concurrence.  Free market.  Offer and demand.


What I mean is that bitcoin allows all miners to compete as far as their fees are concerned.  Hopefully this free market approach should reduce mining fees.

Am I right ?


Title: Re: Building computer for mining
Post by: dacoinminster on January 26, 2011, 01:01:17 AM
Back to the topic at hand (custom mining rigs):

I spent some time trying to figure out how to build one for myself, and how much that would cost. I eventually gave up, because I don't have time for a project like that. However, it would be very tempting if someone were selling purpose-built mining rigs that I could just buy and plug in.

I think it very likely that there is a market (of unknown size) for selling boxes like that - built by someone with PC building skills but no access to cheap electricity and sold to someone like myself who does have access to cheap electricity but doesn't have much free time. Such a buyer would want a PC optimized for the highest MHash/$. All the seller would have to do is set up a simple web store and advertise it on this thread.


Title: Re: Building computer for mining
Post by: bitcool on January 27, 2011, 08:12:08 PM
I gathered some information from this forum and slush's website, here is what I found:

http://i1133.photobucket.com/albums/m586/bitcool5/miningcz.jpg

It's incredible, the growth rate of this cooperative mining is about 20gig hashes per month. If you have a 5970 (~500MHashes/s), your share just decreased from 5% of the pool on 1/10 to 1.7% on 1/27.

With rapidly depreciating hardware (if you try to resell) and rapid growing competition, mining returns are quickly diminishing. It may be very  difficult to build computers, mine bitcoins, and make money. JMHO


Title: Re: Building computer for mining
Post by: bitcool on January 27, 2011, 08:18:48 PM
meanwhile, the total return of the pool has been flattening since 1/7: http://mining.bitcoin.cz/stats/graphs/
which means, the growth of the pool was just tracking the btc network.
of course you can bet the continuous appreciate of the bitcoin, if that's the reason, buying coins for investment requires less capital and is less risky.


Title: Re: Building computer for mining
Post by: slush on January 27, 2011, 09:42:21 PM
The pool jumped from 21-22 to 30 today/yesterday  :-[ and it is not necessarily all new mining capability, some could just switched from other pools or solo mining.

Big jump in today's pool hashrate was done by 13 fresh new 5970 connected to bitcoin network...


Title: Re: Building computer for mining
Post by: bitcool on January 28, 2011, 02:58:34 PM
LOL, I wonder who that would be  ;)
I am just hoping Whoever did this won't keep rolling out 10gig HR every few days, because my share of the pie is getting smaller and smaller by the day  :'(

Actually it all must be a recognition of stellar job Slush is doing.
An amazing job indeed.


Title: Re: Building computer for mining
Post by: bitcool on January 28, 2011, 07:26:54 PM
Your share may be getting smaller per block, but your share per day should remain the same if your hash rate is the same.
I sure hope so, so far I haven't had enough data to confirm this is happening.

The only thing a stronger pooled network should do, is increase how often you get the smaller payments... smoothing out the bumps.
You meant increase the the time interval for the "estimated reward"? I think showing the reward for current block is better, more transparent to the pool participants.
The graphs page does show previous day's total reward, but adding a "most recent x hour total" may be helpful.


Title: Re: Building computer for mining
Post by: Anonymous on January 28, 2011, 10:21:30 PM


It will threaten the network if one pool approaches 50% of the total. Has anyone thought of that?



Title: Re: Building computer for mining
Post by: bitcool on January 30, 2011, 04:52:41 PM
Now I think the income, in dollar term, for average miner may be constant.

There are two factors in play and they have opposite effects:
1. increasing competition and difficulty for the mining operations
2. because of this increased mining cost, the value of bitcoin in dollar term will increase


Title: Re: Building computer for mining
Post by: sethsethseth on February 12, 2011, 09:57:37 PM
I have a crappy video cards in my current rig, and it seems like at current bitcoin prices, I could just go slap a couple 5970's in there and, even at $600 or $700 each, have them paid off in a month or so since I don't pay for electricity.  Is this right? It seems crazy to me.


Title: Re: Building computer for mining
Post by: Fractality on February 12, 2011, 10:29:45 PM
Quote
It will threaten the network if one pool approaches 50% of the total. Has anyone thought of that?

Just wondering, how do the pools work, do they actually assign work to the participants (like ranges of nonces to try)? My thinking was that it probably wouldn't be necessary - my guess is nonces are tested randomly, and the search space is big enough so that conflicts in the pool are unlikely. Am I mistaken?

So if pools don't assign jobs, I don't think they could threaten the network?


Title: Re: Building computer for mining
Post by: Garrett Burgwardt on February 12, 2011, 10:39:59 PM
I have a crappy video cards in my current rig, and it seems like at current bitcoin prices, I could just go slap a couple 5970's in there and, even at $600 or $700 each, have them paid off in a month or so since I don't pay for electricity.  Is this right? It seems crazy to me.

Given that the difficulty is rising quite quickly, the odds of you paying off a couple of 5970s looks bleak. You'd likely recoup a portion but not necessarily all. And if you live with your parents, watch out. They don't want to be hit with an electric bill that is 100 USD higher than the previous month.


Title: Re: Building computer for mining
Post by: sethsethseth on February 12, 2011, 11:09:51 PM
with each 5970 doing 535 Mhash/s as it shows here: http://pastebin.com/AvymGnMJ (http://pastebin.com/AvymGnMJ)
that is one block every 1day 5hr according to the calculator http://www.alloscomp.com/bitcoin/calculator.php (http://www.alloscomp.com/bitcoin/calculator.php)
so i don't see how this can possibly be unprofitable at nearly $50/day in generated value.  Even building a dedicated mining rig seems hard to lose money on when bitcoins are $1 each.  Exactly how fast is the difficulty rising?


Title: Re: Building computer for mining
Post by: Ricochet on February 12, 2011, 11:16:34 PM
with each 5970 doing 535 Mhash/s as it shows here: http://pastebin.com/AvymGnMJ (http://pastebin.com/AvymGnMJ)
that is one block every 1day 5hr according to the calculator http://www.alloscomp.com/bitcoin/calculator.php (http://www.alloscomp.com/bitcoin/calculator.php)
so i don't see how this can possibly be unprofitable at nearly $50/day in generated value.  Even building a dedicated mining rig seems hard to lose money on when bitcoins are $1 each.  Exactly how fast is the difficulty rising?

See http://bitcointalk.org/index.php?topic=2345.0 for some data and charts on that.


Title: Re: Building computer for mining
Post by: Raulo on February 12, 2011, 11:26:59 PM
o i don't see how this can possibly be unprofitable at nearly $50/day in generated value.  
It can be unprofitable if these things happen:
1. Difficulty rises too quickly
Plug different values to this calculator (current hashspeed is about 250 GH/s) and see how many bitcoins you can generate with different assumptions.
http://www.taters.net/btcgc.php
2. BTC price drops
3. Hardware breaks
Quote
Even building a dedicated mining rig seems hard to lose money on when bitcoins are $1 each.  Exactly how fast is the difficulty rising?
Difficulty was rising 13-20% per 2016 blocks since the beginning of the year but the next difficulty increase on probably February 18th is going to be likely more than 30%. The rise in BTC/$ exchange rate lured a lot of new miners.



Title: Re: Building computer for mining
Post by: racerx on February 13, 2011, 03:52:27 PM
o i don't see how this can possibly be unprofitable at nearly $50/day in generated value.  
It can be unprofitable if these things happen:
1. Difficulty rises too quickly
Plug different values to this calculator (current hashspeed is about 250 GH/s) and see how many bitcoins you can generate with different assumptions.
http://www.taters.net/btcgc.php
2. BTC price drops
3. Hardware breaks
Quote
Even building a dedicated mining rig seems hard to lose money on when bitcoins are $1 each.  Exactly how fast is the difficulty rising?
Difficulty was rising 13-20% per 2016 blocks since the beginning of the year but the next difficulty increase on probably February 18th is going to be likely more than 30%. The rise in BTC/$ exchange rate lured a lot of new miners.

But he is correct that todays difficulty and exchange rate means that it is profitable.. today, who knows what tomorow will bring.

Im the the same boat, and am seriously considering cashing in ~700BTC and purchasing a HD5970. Its going to cost me $0 real money for a punt... Though perhaps spending that $700 on buying more BTC's would be a better financial decision?

Plug different values to this calculator (current hashspeed is about 250 GH/s) and see how many bitcoins you can generate with different assumptions.
Not 100% sure what this data means, and what Im supposed to plug into it... eg: here's the result for 600khashes (1x 5970) and the 250Ghashses you said..

Statistics
Current control of network   0%
Coins expected next block   0
Network growth per block   0.014177%
Blocks for network to double   4889.6

Block expectations
Block   Expected coins   USD Value   Network Size
1000   0.11   $0.12   288.075 ghash/s
5000   0.43   $0.44   507.888 ghash/s
10000   0.64   $0.66   1031.8 ghash/s
25000   0.82   $0.85   8651.254 ghash/s
50000   0.85   $0.87   299376.773 ghash/s


Title: Re: Building computer for mining
Post by: Raulo on February 13, 2011, 06:10:52 PM
Not 100% sure what this data means, and what Im supposed to plug into it... eg: here's the result for 600khashes (1x 5970) and the 250Ghashses you said..
5970 has 600000 khashes/s or 0.6 Gh/s.


Title: Re: Building computer for mining
Post by: racerx on February 13, 2011, 06:27:00 PM
oops, missed a few 0's. So how do I discover the current network hash rate?

Using .6G#'s for a 5970 and 250G#'s in total I get this:

Statistics
Current control of network   0.24%
Coins expected next block   0.12
Network growth per block   0.014177%
Blocks for network to double   4889.6

Block expectations
Block   Expected coins   USD Value   Network Size
1000   111.89   $115.25   288.075 ghash/s
5000   429.85   $442.75   507.888 ghash/s
10000   641.44   $660.69   1031.8 ghash/s
25000   822.1   $846.76   8651.254 ghash/s
50000   845.85   $871.23   299376.773 ghash/s


What do the expectations mean? Not sure I understand.


Title: Re: Building computer for mining
Post by: Raulo on February 13, 2011, 07:18:03 PM
oops, missed a few 0's. So how do I discover the current network hash rate?
Here is the graph:
http://bitcointalk.org/index.php?topic=3024.msg42173#msg42173
You can calculate past network hashspeed based on difficulty. The averaged hashspeed that set the current difficulty was
2^32*25998/600=186 Gh/s. Current hashspeed is 230-270 Gh/s (it's hard to calculate it accurately due to block generation variability) which you can roughly calculate based on expected difficulty in the next round:
http://nullvoid.org/bitcoin/


Quote
Block expectations
Block   Expected coins   USD Value   Network Size
1000   111.89   $115.25   288.075 ghash/s
5000   429.85   $442.75   507.888 ghash/s
10000   641.44   $660.69   1031.8 ghash/s
25000   822.1   $846.76   8651.254 ghash/s
50000   845.85   $871.23   299376.773 ghash/s

What do the expectations mean? Not sure I understand.
Assuming the entered hashspeed and global hashspeed growth, you should expect to mine 111.89 coins 1000 blocks from now (about 5 days), 429.95 BTC 5000 blocks from now, etc. Due to difficulty increase, it's going to be less and less each round. If the difficulty increases less, you will get more, if more, you will get less. It is absolutely certain that the difficulty is going to increase as long as mining is profitable. The more profitable, the more people will join mining or expand their mining. It's hard to estimate by how much.  It depends on bitcoin popularity, BTC price and other factors. As you can see, 5970 should pay back itself but if the BTC price drops or difficulty increases more than the entered value, it won't. Due to recent BTC price increases and Bitcoin being slashdotted, the next two difficulty increases will be brutal. What will be next is hard to tell.


Title: Re: Building computer for mining
Post by: racerx on February 13, 2011, 10:50:45 PM
Decisions decisions, not a clear decision on whether outlaying for a 5970 is going to be a prudent decision and pay itself off, Unless of course rates continue to grow. If btc's are x10 by the end of 2011 then its well well worth it. Very exciting times for sure.

Other issue is trying ti actually find a 2gb 5970 in stock anywhere in the UK!


Title: Re: Building computer for mining
Post by: alikim on February 14, 2011, 09:11:39 AM
Has anyone tried to use encryption chips, which have SHA256 hardwired in them?


Title: Re: Building computer for mining
Post by: bitcool on February 19, 2011, 02:27:28 AM
Now I think the income, in dollar term, for average miner may be constant.
There are two factors in play and they have opposite effects:
1. increasing competition and difficulty for the mining operations
2. because of this increased mining cost, the value of bitcoin in dollar term will increase

Big block production drop (30%) today due to difficulty increase:
http://mining.bitcoin.cz/stats/graphs/

It may take a few more days to work out excess due to recent surge in mining investment. For the longer term though higher difficulty begets higher $ value.

I expect btc $ will trade between $1.20~$1.40 soon.