Bitcoin Forum

Hello Everyone,

I'm thinking about building a mining rig, but with the difficulty of mining rising exponentially, is it still profitable? I'd be spending $600-$800, and would probably get somewhere around 0.5-1.5Ghash/sec.

Any insight is appreciated.

EDIT: The rig would be up and running in about 1 and a half weeks, and the difficulty will be even higher by then.

Rig building is still profitable and my guess is this will still be the case for some time. The problem is your returns will keep diminishing so you'll face an ever slowing ROI. It's hard to say how long it will take for you to recoup your investment, but with such a small sum I don't think it will be longer than 6 to 8 weeks. The last difficulty jump was huge but the next ones are bound to be a little smaller, if you take some history into consideration. There was an investment calculator spreadsheet floating around on the forum...

Keep in mind though that at any one time somebody can plug the giant cock of doom into the grid and screw us all with 3 THps jizz rates.


As a side note, if it's just gains that interest you, I think (and most people here seem to agree on this) that you'll be far better off by simply buying bitcoins for those money. With the grid hash speed being what it is now it's safe to say that BTC production will slow down eventually and judging by its growing popularity, prices will climb quite a bit more. It's your call though.

marginally.
in countries with inexpensive energy and skilled people.
but when complexity grow up and/or other[than hash-related]workload become ordinary its become hardly marginably at all.
if you ALREADY had horserpower you may try use it.
but build specially for mining ..

How are you planning on achieving 1.5 Ghash/sec with an $800 budget?

5870's are $250 apiece at the moment and each only get around 350 Mh/s and are one of the most cost efficient GPUs at the moment. Even 3 of them would not get 1.5 Ghas / sec and that's not including the substantial cost of the rest of the equipment that goes with a computer.

well, in fairness, he did say "0.5 - 1.5".

two 5870s can be had (recently, anyway - if not today) for $225 each - and the rest of the box (CPU, motherboard, RAM, the box, a couple extra fans, and a PSU [all software is free, of course]) can be put together for $225 if you're careful and maybe a bit experienced.

and really, you should be able to get 775 Mh/s out of a couple of 5870s without trying too hard.  i do.

his numbers work.  and mining is still quite profitable.

I started mining back in March...I would have been much better off putting that money directly into bitcoin due to the appreciation in that time.  If the price remains stable however, it will be good for a few weeks until difficulty catches up and diminishes the profit margins.  Then you have to hope for further price increases.  But, with mining you own the hardware and could later sell.  For that reason, I view mining as a lower risk way of obtaining bitcoins, but one that may not pay nearly as well compared with buying bitcoins directly.  Also, don't underestimate the amount of time you'll spend on mining.

I have made it my new aim to convince everyone that mining is NOT profitable.

So no, rig building is a terrible investment, and you will lose all of your money.  And your home.

Due to recent developments I have to agree, it's like or better yet worse than throwing money into a wishing well at the moment.

"recent developments"?

hmmm...  i dunno - i do quite well.

i started seriously in march, paid my rigs off in about three weeks, and now 1-1 1/2 days' mining pays my monthly electric cost.

i must've missed the memo.   ???

This argument comes up every so often when talking about the profitability of mining, and it has always somewhat bothered me.

If you take two persons:
Person A) Is thinking about buying a used computer for $1000, planning to use as a dedicated mining rig.
Person B) Already owns a same kind of computer with resale value of $1000 just sitting idle, and plans to start using it as a dedicated mining rig.

Now B has an option to sell his computer for $1000 or start mining. Person A has an option to not do anything, or buy a computer for $1000 and start mining. In both cases, if you decide to start mining, you will end up initially with $1000 less money compared to when you decide to not mine, so they are economically the same decisions. Of course in a lot of cases, situations are not this simple and there are some other factors to consider, but still if I presented these two exact scenarios separately, I predict that the same people would recommend person A to not waste his money, and for person B to start mining.

I noticed that eventually the plan is that people will be paid for processing transactions instead of mining, so at what point do you think enough people will be paying for transactions such that transaction processing to be profitable?

If that were the case, would it be worth running a machine to process transactions instead of just mining?  Am I missing something, entirely?

its had other overhead, than buying hardware cost and paying electricity.
and bigger you solution, bigger # problems you have.
starting from cost of you time.
if its you personal PC - its one thing.
then you need [costly]space for it, power/air supply, support, etc.
people then forgot about it, when they ALREADY paid for that all for personal purpose.
and talking about profitability, using bitcoin-farming-targeted PC' from animation rendering[movies for example]and science computing for separate contract can be 15x more profitable, according for current prices for such resources and GPU's performance on such tasks. and thats become ordinary, after someone write OpenCL appz for such things. i mean, complete solution[like nowdays hashminers], not only GPU renderer or molecules crunching, in "press here and install" package.

Mining is how transactions get processed.  Every 4 years or so, the fixed part of the blockfinding reward halves.  The theory is that the transaction fee will gradually increase as that happens to ensure that miners keep getting rewarded.

Don't users have to voluntarily provide a transaction fee though?  We're not getting paid right now for any transaction fees are we?

Transactions is mining. It's extra bitcoins you get above the 50.00 per block (that will diminish).

I'm starting to see about 0.03 worth of TX fees in each block: it's definitely already making a small impact...

Ah, got it now.

I'm still a bit new to the game, so all the terms/jargon is getting mixed up in my head between blocks/shares/transactions/ etc., etc.,

Thank you very much :)

i tell short story then.
one of my friends, on my answer "why you do that, cuz its under $xx income in best case?", answer "im got four kids, so even extra-$20/month matter". he usually put his PC[one 5870 GPU if am not forgot soemthing] into mining mode, only when he out[and his PC unused].
for similar purposes its ok: to extract some extra-income from already bought and underutilised hardware.
but build specifically form mining... keeping in mind relatively near complexity skyrocketing... not matter.

to answer the initial question: yes, it is.

let's say you only get 2x5850 (not 5870s) for $800,
2 5850s get around 700MHash/s and the rig will need ~375W (probably less, but let's just be sure),
at (very expensive) $0.3 per kW/h you'll pay $2.7 per day
at current difficulty the expected average output is 2.88BTC per day,
at current market rates (of roughly $6.5) that's $18.72 per day.

$18.72 - $2.7 == $16.02 per day
16 / 800 == 2% ROI per day

show me an investment opportunity that pays you 2% per day and i'll join it.

I'm hoping im profitable enough to pay off my rig.  I just spent around 800 on a rig that includes 3 Sapphire Xtreme 5850's (which are on backorder for another 2 weeks GAH!)

I plan on using the rig at my office in my test lab (since I work in IS/IT) so, i wont have to pay for power :)

Is it possible this rig will be profitable when the cards come in in two weeks, if I am not paying for the electricity?

This was my initial thinking, but then I started accounting for predicted difficulty increases and it looked less hopeful; clearly I'm new here, so feel free to point out any foolish mistakes, but here's how I was looking at it:
The $16/day figure applies at current difficulty, which should last for another 10 days or so (probably less, looking at the figures on blockexplorer.com), so that nets you $160 total. A guesstimate based on the previous data would optimistically suggest a difficulty jump of 40% (again, quite possibly more), reducing the daily income to (18.72/1.4)-2.7=$10.67. Say the difficulty levels off somewhat, you might make a further $130 or so at that price, followed by another 20% jump, giving a subsequent daily income of (18.72/(1.4*1.2))-2.7=$8.44. Your daily revenue has halved in less than a month, and break-even might take three months total. Investing in more hardware can't help with break-even time, since Mhash/$ remains largely the same, although it will make the absolute potential profits higher once you do pay off the investment (at the price of a higher risk if the investment is not paid off for any reason).

Of course, the key point left out here is the changing value of the bitcoins themselves - the overall trend seems to be that value very approximately tracks difficulty, so if you're confident that the increases will continue to more or less offset the difficulty increases then my 'diminishing returns' theory is totally irrelevant. It also doesn't account for the resale value of the rig, which diminishes, but may be enough to generate an overall profit once mining itself becomes unprofitable.

Basically, I'm not saying that mining is a bad idea, just that it's a moderately high-risk investment which is inextricably linked to the assumption that the bitcoins themselves will continue to increase in value faster than the increase in mining difficulty.

Actually, I did calculations too and:
Today Im earning 23$ per day (after paying bills) then +35% difficulty
In 10 days - 16,1 $ then +30% difficulty
In 20 days - 11,5 $ then +25% difficulty
In 30 days - 8,3 $
After 40 days  ~600$
After 60 days ~713$ (few more difficulty rises)
I just assume that price wont change and Im good in predicting difficulty rise.

To get 23$ per day with current difficulty you need to have around 3.8 BTC per day, which gives 920Mhash/s (3x 5850)

If the price stays at 6.8$ most prolly u wont get back your cash, so your investment is risky.

Nope. Stop building rigs!

Ha, best description ever. All the replies post this were just people talking to hear themselves.
Though I disagree with the buying coins bit, excepting that it helps grow the bitcoin pool o' cash which will help keep it alive.

why do you predict the difficulty to continually rise, if the price doesnt change at all?
the price will change.

i won't and can't predict the future,
i just don't know, what the difficulty will be in 10, or 20, or 30 days
and i also don't know, what the price will be in 10, or 20, or 30 days, maybe it's more, maybe less than today.

it is profitable now and the last year has shown, that price and difficulty will catch up on eachother,
right now, the price leads the way, and difficulty follows, it might be the other way around in 2weeks.

it's always the same with every single difficulty jump,
everytime people start complaining that mining isnt profitable anymore,
fact is, it's more profitable today (at a higher difficulty), than it was a few weeks ago (at lower difficulty) due to the fact, that the price is so incredible high.

let it be a bit less profitable next week, or next month,
i won't care, less profit is still profit.

Keywords: at current difficulty rates.

The OP admitted that the rig won't be up and running for another 1.5 weeks, at which point the bitcoin system will already be into the next difficulty. Therefore, none of your numbers apply to anything the OP will see.

Some times I can't tell if people forget about the rising difficulty, or just choose to ignore it because the numbers are so much better if you do. Thanks to the members here who keep pointing this out. Note that most of the projections here that take rising difficulty into account have the OP breaking even at some time in the future (2-3 months), at which point the difficulty will be so high that income will be a trickle. The only profit you're likely to see is from selling your hardware after the fact, but remember that plenty of other people will be eager to unload their ATI cards by then. That's a far cry from all of the claims that mining is 'very profitable' still.

yeah, it has always been that way
and you always tell people, they shouldn't invest into new rigs,
yet those that do made profit and probably already paid off their new rigs.

very strange that mining for me has always been like "assuming difficulty rises, but price doesnt, it might become non-profitable in about 3months",
it was like that in october, when i bought my first ATI card, it was exactly the same when i bought the second card in december,
it was still the same when i bought 2 other cards in february and again 2 cards about 2-3weeks ago, everytime i had at least 3month in profit assuming the price doesnt rise at all.

and guess what?
today that same (pessimistic) calculation tells me, that mining might become non-profitable around september,
so the risk to take isn't any bigger than it was half a year ago.

but we all know why you tell everyone not to invest in rigs.  ;)

That isn't a safe assumption at all.  The next difficulty level is going to be a doozy.  If the difficulty level were to increase today it would already be at 330,000.  And it just increased to 244,139, what, two days ago?  When the time for the next difficulty level increase comes you are going to be shocked by how much it has risen.  It's effectively already gone up 35% just in the past few days.

Estimate difficulty is around 326,000 right now only because:

Average network hashrate on last difficulty level: 1.8 Thash/s
Average network hashrate on last difficulty level: 2.1 THash/s
But, hashrate at end of last 'jump' : 2.1 Thash/s
Means that difficulty is based on average performance on network, so even if performance is not changing, next jump can be huge.

Yes.  But everyone thinks that means it will go up, but in reality it has gone down. 

you can get 5850 for less than $150, and they hash at 250-300 MH/s, even 400MH/s if it's overclocked (convery did it).

you are missing the time you put into setting up and watching the rig. that is gonna be a couple of long days work depending on your experience. if you would work for money and buy bitcoins you would be much better off. so the question is: how much fun is it for you to play with the rig?

Two long days to set up a rig?  Good lord, I don't think it's ever taken me that long.  My first build took all of 3 hours to put together, and the most recent ones have been done in under an hour.  Install OS, install drivers, ready to go in under 2.

Anyone who takes two long days to put together a computer really shouldn't be putting them together to start with.

well yeah, SgtSpike - two hours is about right.

but everybody has to start somewhere.  took me a couple of days to build out my first 286.  getting that CGA card to work was a bitch - i wonder how many milli-hashes/sec it would have done...?

Quite an absurd comparison. I never said buying a mining rig or hardware was unprofitable back in October, or in December, or in February. 2-3 weeks ago I said that the only way buying mining hardware would be profitable is if exchange rates went up, and sure enough they did. Of course, my point was still that you'd be better of buying bitcoins directly if you were convinced the exchange rate was only going up. And I was correct. If you had bought bitcoins a month ago, you'd be doing way better than mining. But I don't think bitcoin exchange rate increases are going to continue.

The point is: Going forward buying a computer just to mine isn't going to be 'very profitable' like so many members are convinced. Difficulty is skyrocketing, so any comparison to last October, December, etc. is entirely irrelevent.

And please drop the conspiracy theory ad-hominem already.  ::)

Yeah, but then you increase the overhead costs as a % of total rig cost. Since for every 2 graphics cards, you need to spend about $300-$400 more to buy the case, power supply, CPU, motherboard, optical drive, operating system(this one is optional albeit).

No, building a new rig from scratch probably will not become profitable for you unless the value of bitcoin increases dramatically in the short term.
If it's a matter of just slapping in another video card to your system, it probably will be profitable or at least break even.

For the BTC value to increase, more commerce needs to occur with it.  Simple as that.  Anything else (like trying to tie BTC value to hash rig value...) is a bubble market situation.

And this is why you might as well just buy bitcoins, the only way you are going to recoup your money on a dedicated rig, time to buy build and manage it, and make some money, is if bitcoins value increases, if that is the case, then why not just save yourself a whole lot of time and energy and simply buy bitcoins with your money.  Well there are a few I can think of: building a rig is fun for most people doing it, you can't play a game at 150fps on your bitcoins, the resale value of the rig makes it a less risky proposition than simply buying bitcoins.

It's awful tempting for me to keep adding more mining power to keep my bitcoin production from falling as difficulty rises, but I'm quickly going to exceed what my infrastructure can currently handle.  Mining is addicting, however I have to keep reminding myself that if I'd had just put the money I have spent on rigs into purchasing bitcoins, I would have had 5x the number of bitcoins that I have right now and a much (much!) larger profit.  It's not that mining isn't profitable, it's just that if you believe in the future of bitcoins, you might be better off putting cash into bitcoins directly.  I'm glad I have the mining capacity that I have...it's nice to have been able to keep generating bitcoins rather than chase the market higher...but now that the price seems to be dropping, I'm scaling into bitcoins directly rather than buying more hardware for mining.

I don't think building a new computer a week from now just for mining will be profitable. I think the value of bitcoins are going down in the near future anyways. If you want to build a gaming computer or upgrade your current nvidia 9600 and mine when you aren't gaming you might not get back your money but you will recoupe some of your investment.  Remember mining will burn out your hardware faster than normal use.

No it won't.

Where a work the hardware that runs above 65 C burns out faster than the stuff that runs below 55 C at a cost of hundreds of thousands of dollars.  Then again all the lasers and electron guns don't help much.  I have already wrecked my old HD4850 running constantly @ 73 C so I assumed that the same trend I see at work would apply to mining.

Yes, it will.  Consistent full load will create more heat than normal usage.  Heat is a major factor for hardware failure.  Anything above 55-60C for long periods of time is probably contributing to what manufacturers would call "abnormal wear".

I dont think the OP was positing that mining will burn your shit out tomorrow, but unless you are water-cooled or are otherwise extremely thermally balanced, make no mistake, you are subtracting life from your hardware.

If building a rig isn't profitable, would just upgrading a video card still be worth it?

Anything above 60? pff..no way..radeon cards for example are ok with temperatures way above that.

But see, other people have had cards die shortly after purchasing them out of the blue as well.  Or die during what would be considered "normal use".  Just because yours died doesn't mean that heat was the cause.

The higher the temperature, the shorter the lifespan. It's not a matter of drawing a line at a certain temperature.

Remember, we're not talking about the card just dying 10 minutes after you start your miner. It's a question of reduced card lifespan and MTBF.

Voltage is a big killer too, for anyone who might be considering serious overclocking.

Tough call really. When mining clouds were rare back in my time last year, the cost was not worth it because the value was 1 BTC -> $0.001 almost.  But now, even though they cost much more to produce than the value, the long term investment makes it worth the cost now.

I wouldn't look at a mega-rig as a short term lotto, but more like a long-term investment. If it cost $1k to only mine $500 worth of BTC, it doesn't make sense in the short term, but if a year from now that same BTC that you spent $1k to create was now worth $2k in value, then you have a good long term investment.

So if you want to play the day-trading like the stock market, buy/sell BTC with the market wave. If you are looking for a more long-term investment, a mega-rig might be the answer if you are willing to take that long term risk. The rig could die early or it could hum all year and produce a nice vacation fund for the family.

It's all about risk.

This doesn't make sense.

Your example requires the exchange rate of bitcoin to quadruple (BTC value from $500 to $2000).

If you're so sure that will happen, why would you spend $1K on hardware to acquire $500 worth of bitcoins, when you could instead spend $500 and get $500 in bitcoins, doubling your return?

The BTC value is going to go down, way down.  Its quite simple, before 2 days ago I had never heard of bitcoin, I have a 6950 sitting idle that is now generating bitcoins, there are millions of people exactly like me who have never heard of bitcoin, there is 0 out of pocket expense for them to start generating bitcoins at a much more efficient rate than you can, and they dont have to buy anything.  As they come online the production of bitcoin will explode and the price will fall dramatically, how much, quite simple, down to the rate at which they are barely profitable from an energy standpoint, for me since it costs me $0.24 to generate a bitcoin, I would guess the value of bitcoins to be $0.25 - $1 in the long term.  Of course as the value drops more people will stop producing bitcoins since its not worth the time or hassle leaving the price somewhere above the raw energy costs.

That's why I don't overvolt or overclock my cards. I intend to squeeze as many bitcoins out of them as possible for as long as possible.

Although the logic of "higher the temp the shorter the lifespan" is valid I don't think there is a way to measure or to know when and if the card(s) will fail. I think it's more likely that the fans will die before the actual GPU die will somehow fail. What's worse for a card is cold and hot cycles..running it at a constant temp I think is far better..no thermal expansion and contraction cycles which can mess with the soldering.

It looks like the summary of this topic so far is that rig building is only profitable if you already have the hardware or you get your hardware at a discount, and if you expect the value of the bitcoin to appreciate.

Correct?

Gamover the supply of bitcoins is not going to dramatically increase as you suggest. read about how the difficulty changes every 2016 blocks. if all these people with idle gpus start mining the rate at which blocks are found will increase but then the difficulty will adjust so that on average 1block/10 minutes will be found (or ~2016 every 2 weeks). the algorithm is constructed to maintain a steady supply over time so the production of bitcoins won't explode like you suggest

I agree, the supply can't increase, but the value is going down, as more people mine in the background because they already have the hardware the price will go to the cost of power required to make the coin, since difficulty is going to increase as you pointed out, the price will increase over time, but from the base cost of $0.25, not from where it is today.  Anything over the base cost, plus some profit, plus the freedom of anonymous payments, puts the bitcoins real value at somewhere around $0.25 to $0.50, the $5 - $8 figure we are seeing is because of pure speculation, it has nothing to do with 'demand' of bitcoins since anything you can buy with them can be bought with normal dollars.

Eventually demand will catch up and prices will skyrocket again. Remember that there will only be 21 million BTC out there EVER.

My gut feeling tells me that the cat is already out of the bag and that price will not go below $1 again.

Is the value of a penny based on the cost to produce the penny? No.

Is the value of gold based on the cost to mine the gold? No.

So why do you assume the value of bitcoins will be equal to the cost to produce them? The value of bitcoins are based mainly on supply and demand.

A penny is part of the reserve currency of the world, gold is a physical limited resource that has manufacturing value, bitcoins are neither of these, it is a made up virtual notion and exists only in theory.  Other than speculation why does anyone 'demand' a bitcoin?

Anonymity.

Transfer of value without fees to central (i.e., banking) authority.

Unstoppable transfer across borders.

All excellent qualities but do you think they are worth 95% of the value of the bitcoin?

they are if you require them.

Do you have any hard technical data you'd like to share to support this assertion or is it all from your rectal knowledge base?


Since there are no futures contracts and the prices on the exchange are what people are actually trading BTC for cash, speculation doesn't have anything to do with it. It may or may not be overvalued but the market will determine that.

There value is enhanced with relatively low exchange volatility.  With low volatility the demand comes from anonymous exchange outside the banking system.

If the exchange rate is relatively stable then it does not matter what the US$ "price" is for BTC to have value in trade.

The difficulty has been increasing more-or-less exponentially since the first increase 30/Dec/09, see http://forum.bitcoin.org/index.php?topic=43.0

http://forum.bitcoin.org/index.php?topic=1918 (http://forum.bitcoin.org/index.php?topic=1918) In this thread I calculated the expected number of blocks you can ever generate, assuming an exponentially increasing difficulty.  I've refined the calculation a bit - the original didn't take into account the fact that the time between difficulty increases was not 14 days, but shorter, depending on how fast the 2016 blocks between increases are generated.

I won't go into the details, but the equations are:

E = Ch/((a-1)D)
P₀ = exp(-E)
h_0.5 = -(a-1)D ln(0.5)/C

Where:
C = 0.0002818  is a constant
h is your hashes-per-sec:  1Ghps = 1x10⁹
a is the difficulty increase factor, i.e. if difficulty goes from 20 to 30, then a=1.5
D is the current difficulty
P₀ is the probability that you will never (never ever ever) generate another block. See note 4 for the meaning of "never".
h_0.5 is the hashes-per-sec that you would need to have a 50/50 probability of generating just one block.
E is the total number of blocks you can expect to ever generate, ever.  See noe 4 for the meaning of "ever".

Current values are:
D = 244139
a = 1.3435 (see note 1)

Therefore, with 1Ghps:
E = 3.36 blocks
P₀ = 0.0347
h_0.5 = 206 Mhps

So, if you do buy the rig, you have a 3.5% chance of never ever generating another block.  You can expect to create 3.36 blocks = 168 BTC = $1092 at current exchange rates.  To have a 50/50 chance of creating a block, you'd need to have 206Mhps (this has nothing to do with you and your rig, it just gives an idea of what the entry-level Mhps is - a top CPU now would generate at most, I expect, 10-12 Mhps).

On the other hand, if you buy $700 of bitcoins now, then you'll have 100 bitcoins right now.  That's about 2/3 of what you can expect to get spending on a rig and generating.  All depends on whether you think the price is gonna go up or down.  Good luck.

Notes:
1. Difficulty is assumed to rise exponentially forever.  This is incorrect, but it's holding up much better than I would have expected - see attached graph.  The inset to the graph shows the difficulty increase factor.  If we average this value over all blocks since the first actual increase in difficulty, we obtain the value a=1.3435
2. Eventually the reward for a block will halve, then halve again and so on.  You can expect 3.36 blocks, but if they happen to be generated after the reward halves, then you'll get less than 168BTC.
3. If you mine solo, then you won't get 3.36 blocks, it'll obviously be either 2,3,4,5 or whatever.  If you mine in a pool, then you can expect a reward equivalent to 3.36 blocks, less the pool's fee.
4. You will receive these bitcoins slowly.  When I say "all you'll ever expect to generate", I really mean "ever" - from now until the sun goes nova and swallows the earth. However, I expect that the exponential increase will stop before then, for one reason or another. Likewise "never".
5. You'll have to add in electricity costs.
6. These values for E, P0, h0.5, assume you start mining *now*, if it takes you a month to get started, then adjust for the difficulty at the moment you start.

If this post saves you money: 15BHRM52yuzjNyvkrdu8dcWFnfpK6eWsXm

I tried to upload a graph, but a message says the upload folder is full, please contact an admin.  Any admins listening?  In the meantime, I've put it on ubitious: http://ubitio.us/file/download/328   I can't help that you have to pay for the file (BTC 0.02), but as soon as I can, I'll attach it here.

EDIT: the graph is simple really, it's just a graph of difficulty Vs time, with an exponential fit, and also another curve showing the difficulty increase factor.  All info for it was taken from blockexplorer.com.

Suppose your employer has unmetered electric (office park rental).
If your employer pays you $1000 it will cost him $1073
After taxes you will see $900.

If your employer spends $1000 on a graphics card + case + power supply instead of paying you, he saves $73.
If your employer lets you use the GPU to mine for your own address then you can generate 2-3 BTC a day with a ATI 5970.
At todays prices that would be $20/day or $7200/year.  Of course difficulty will go up and price may vary.  If we use your numbers then $1100 over the life of the rig.   

Now if you factor in that every employee already needs a case+power supply + graphics card, the real cost to the employer is only the delta
between the $200 graphics card and the $750 graphics card.  I suspect that the net cost to the employer is $600 to turn your desktop into a mining computer.

So if you approach your employer with the offer to take a $1000/year pay cut in exchange for $1000 worth of "upgrades" to your office computer then your employer saves $73 dollars and you earn $200 extra using fergalish's numbers and if the price/difficulty works in your favor then potentially much more.

Now if your spousal support payment is based upon your W2 income, then this is a clear win for the employee and always a win for the employer.

Total mining n00b here, so please correct me if I'm way off...

If the 50% difficulty jumps continue, what number of BTC's and/or $'s will your brand new rig generate in it's mining lifetime?
Suppose you start it up just after a difficulty jump - in the 10 or so days until the next jump, you will generate X number of BTC's per day for a total of 10*X BTC.
Then the difficulty jumps by 50%, so in the next 10 or so days, you will be generating (2/3)X BTC's per day for a total of 6.67*X BTC. This will then drop to 4.44*X BTC, 2.96*X BTC, 1.97*X BTC, and so on, every 10 days.
Summing it all up, you come to a grand total of 30*X BTC. That's it. That's what your rig will generate in it's entire lifetime. 90% of that will be generated in the first 2 months - after that, you might as well unplug it, because it will no longer cover the cost of electricity.
I think it's worth emphasizing one more time: if the 50% jumps continue every 10 days, your brand new rig will only ever generate 27 times the BTC's it generates on its first day!

So, if you just got a new rig with a pair of 6990's on May 19th, you are probably generating something like 6.4 BTC/day. By mid-end July, you'll have generated some 170 BTC's, at which point it will become uneconomical to operate. Selling those BTC's at current rates will net you about $1100. Subtract electricity costs of $100+ for a total profit of some $1000. Of course, you will also lose something like $500 on selling your rig (you'll have spent about $2000 on it and maybe sell it for $1500 after two months), so that further reduces your net profit.
Now suppose you're just thinking about building your rig; it might take a couple of days to get the parts together and set it up... just in time for the May 27th jump. Your rig will now be good for just 2/3 of those 170 BTC's, so about 113 BTC/$750. After electricity costs and devaluation of your rig, your practically down to break-even!


Now, of course there were a lot of assumptions in this scenario:
- difficulty jumps continue by 50% (when in fact they seem to be getting even worse)
- difficulty jumps continue every 10 days (when it's currently more like 8-9 days)
- BTC/USD remains stable (it could go either way really)

Realistically, the exponential growth of the network's hashing strength will not continue indefinitely. But it doesn't have to - just a couple more 50%/10 days difficulty jumps will mean the currently added rigs will never break even. The fact that the jumps might even exceed 50% and/or be fewer than 10 days apart just makes the problem (exponentially) worse.

I fear we are already at the point where if you bought a new rig today you would never break even.

Exactly, which is what you would expect to see, because obviously the state of affairs where new hardware pays for itself just in BTC generation was never going to last indefinitely.  Eventually the rewards for mining should go down to around the cost of electricity.

There is still the potential to multi-purpose assets in environments where the cost of electricity is externalized. 

Hi tread starter. I hope you don't mind me linking my tread to yours. I'm consolidating build discussions :)

I'm thinking that once it becomes uneconomical to operate a miner, a lot of people are going to drop out of the game. When this happens, we'll likely see a mass exodus of miners. What will then likely happen is that we'll have less computing power to discover blocks and the difficulty will have to decrease. The people who never stopped mining following the exodus would then be in prime condition to take advantage of the rebound would they not?

People think that the difficulty can only increase, but it's possible for it to decrease in order to meet the block production rate is it not? We're also assuming that the value of the coins doesn't increase. If the value decreases AND the difficulty increases, then we'll definitely see an exodus and the greater likelihood of a corrective decrease am I right? It might be a matter of who can operate at a loss the longest.  

It's like the stock market, if you really think bitcoins have a lot of value and will eventually increase, you'll be able to hold onto your shares as opposed to selling them off.

Assuming the following numbers, which I feel are more or less average (correct me if I'm wrong):
Rigs costs $1/Mhash, and hashes 2Mhash/W
Electricity costs $0.15/KWh
Rig depreciates in resale value 50% during the first year

I buy a rig that does 2Ghash for $2000, which uses 1000W of energy. Electricity costs over the year are 0.15*24*365=$1314, and during the first year my rig depreciates in value $1000, making the total $2314. So if I wanted to have a nice ROI of say 30%, I would need to earn 2314*1.3=3008 yearly and 3008/12=$250 monthly. Assuming current BTC value ($7.32), (according to http://www.alloscomp.com/bitcoin/calculator.php) my 2Ghash rig would do that at 1800000 difficulty, which is about 7 times higher than it is now. So while the difficulty has still a lot of room to grow, assuming the BTC value stays where it is, I would be VERY surprised if the difficulty stays above something like 2000000 for any significant period of time. And considering that I didn't count in all kinds of additional expenses like time you have to put into it, or risks like hardware failure and others, I believe that the threshold where a lot people stop adding rigs and/or quit mining is actually going to be well below 1800000. Changing BTC prices will naturally move that threshold up or down.

Point being that any calculations based on exponential growth of difficulty to the foreseeable future are nonsense. It will grow (exponentially or not) while there are profits to be had, but no more.

Bitcoin mining is not a get rich quick scheme.
Profit margins like you can get today will NOT last, and are shrinking VERY quickly. It's only possible with a really quick rise in BTC value while the hashing power is playing catchup, like right now.
If you build a rig now that does way less than 2Mhash/W in a place where electricity costs more that $0.15/KWh, you might be in for a rude awakening in a few months.
However, if you concentrate on being more cost efficient than an average miner, you should get a reasonable ROI, assuming that significant portion of miners refuse to mine at loss.
Your definition of reasonable ROI may of course differ from mine.

Mining power will not drop...
People are not smart...
When it comes to economics...
You are dreaming...

Every day new people find BTC...
Mining is very tempting...
Get money for free...
Most don't consider electricity...

Building rigs are still profitable...
If you get super cheap components...
The losers will be those who overpay...
For nice case, mobo, CPU and RAM...

With current difficulty plotted to go up 100% this morning - anyone who is building a rig for mining is going to have a long wait to pay it back.

I know that alot of people don't quite grasp the power of doubling - but it's real. I'm fairly certain most of this capacity is being brought online by those that do the simple calculations without really looking at difficulty increases, trade differences, etc.

I have been in business for myself for the last 15 years, working in the networking/technology centers. I have a datacenter and thought to myself - well things have gone well - this looks like a nice little side income - so I started to crunch the numbers and came up with the fact that if you want to build rigs as a business, or are continuing to buy them *right now*. If our present course stays true, you will be waiting a long time to get your money back.

If you think that rig building is still going to be lucrative enough to continue to fund new hardware purchases with a reasonable ROI time, you might be suprised. Taking the 50%-100% difficulty increases we have (and will) continue to see in the coming months - I would like to present some basic numbers:

Let's take an example $6000 investment I was contemplating to get ~5000MH up and running for a period of 6 months (with .09kwH commercial electricity) from today.

First some assumptions:

Mining Rigs Cost: $6000
Electricity Cost for 6 months: ~$1000
Weekly Bitcoin Rise: 8%
Weekly Difficulty Rise: 100% (based on our next difficulty projection continuing from 500000+ as seen at bitcoin.sipa.be)

At the end of 6 months difficulty is @: 999424000 and Bitcoins are trading against the USD for: 1 Bitcoin=16.49626495810

Assuming you don't sell your bitcoins early and wait for the 16.49 price you will yield: $5628 Gross

Subtract: your $6k in equipment, $1k in electricity and you end up with a loss of $1372 - lets say you sell the rigs for $1500, well you just made $128.

Shorter times don't help - they just make the hurt worse - assuming 3 months your total value of generated bitcoins is ~$2032USD - it doesn't take a genius to figure out that spending $6500k over 3 months to yield $2032 does not == profit.

Perhaps you say 100% difficulty increase isn't realistic, ok take the numbers down to 50% and your 3 month profit is: $5079 - still short of the $6500. Again this assumes that bitcoins continue to go up in price.

This of course assumes that Bitcoins rise *every week* by 8%. That means in 6 months bitcoins are trading at ~$45 USD per bitcoin. If you are relying on bitcoin trading stronger against the dollar to float your mining business model - my suggesting would be to buy bitcoins instead of rigs.

If you took that $6000USD you would have spent on hardware and instead put it into coins RIGHT NOW - then you would have bitcoins worth ~$45,000USD in 6 months and ~$17,000 in 3 months. A far better profit margin, with alot less work.

Me personally, I'm spreading my bets by reducing the size of the hardware to something I could use as a decent gaming rig when I'm done and putting the rest in bitcoins. To help the economy along, I will also be accepting bitcoins at my business (currently customizing a shopping cart for it).

However, a lot of the more effective mining gear for the price (I.E. 5850s, 5870s, etc.) have gone out of stock and/or greatly increased in price. I recently bought two 5850s for 140 dollars and one 5850 for 180 dollars. I have them overclocked to obtain around 960 Mhash/sec total. Since I bought them, they're now back to selling for ~300 dollars if you can even find them. This is going to edge people out of the game.



Oh, there's definitely no doubt that buying bitcoins is greatly more profitable than buying mining hardware. However, I feel as though the difficulty is going to level out or drop as people begin to realize it's not profitable. Those people will then drop out and there will probably be a mass sell off of hardware I would figure. The difficulty would then adjust for those people that are still hanging on I feel. Again, the bitcoin price is what is going to dictate if people deem it is profitable or not to mine.

I do feel as though a 100% weekly increase is somewhat unrealistic. The difficulty is probably going to level off. People are simply getting into mining now because bitcoins are 7 dollars apiece.

 
That's a good idea, I'm going to consider doing this as well.

I like your strategy, hope you don't mind if I adopt it :-P.

I don't need to post technical data, any idiot can calculate the raw value of a bitcoin at any time, simply use your hash rate, difficulty, and the price of electricity you pay, $0.12/KWh and 360Mh/s works out to be around $0.25 per bitcoin, given that the other features of bitcoin must have a value of something, I put the value slightly higher, of course those same feature may be a negative to many people.

Knowing this and that nothing of value is sold exclusively in bitcoins leads me to believe the rest of the value is purely speculation (people buying them in hopes they will rise in value).  A huge price correction is on the horizon as others in the post have spelled out (amazingfunksta).  As soon as people realize the nonvalue in bitcoins and mining them, you will see a huge dropout, followed by a huge price decline.

excellent post and my same conclusion, I have been in the tech biz for 20 years, 15 years of that on my own biz, I think a lot of the recent price increase came from people not really analyzing the data and understanding the returns over months.  when i first heard about bitcoin last week i was super excited about it and fired up my 6950 immediately while i crunched the numbers for a planned roll out of several machines with 4 5850s each, there are still many available (8 on craigslist in my area) after some rather simple analysis there is no way in hell i would do it, there are simply too many unknowns and all profit is dependent upon bitcoins value increasing by a lot, and if that is the case simply buy bitcoins...

my predictions:
bitcoin value goes to cost of electricity over the next 45 days
mass exodus on market and fallout of bitcoins value thereafter
excellent time to buy bitcoins as value should increase back to electricity cost
bitcoin market slowly recovers or entire bitcoin market is gone
flood of 5850, 6990 hit ebay, great time to upgrade your card :)
Satoshi Nakamoto releases iCoin project to replace bitcoin

Bitcoins value is not linked in any way to the amount of electricity it takes to generate it.

The long term success of Bitcoin will depend on an economy being created around it. There are people trading BTC for goods and services. Go read the Buying and Selling threads. If you believe that it's mostly speculation, that's your opinion. If you are so sure that the price is going to bottom out then you should find someone willing to make an options contract with you. You'll be speculating too.

BTC value is not linked to difficulty either. A huge dropout would cause difficulty to lower and make it easier for the miners still mining to get more BTC from their mining operations. The only way that would effect the market would be the miner that gave up selling their coins. The chances of someone dropping out at this point from being fed up and having enough coins to flood the market and crash the price is most likely pretty low. The miners with the most coins are the ones who either have been around since the beginning or the ones who put a huge amount of capital into mining. Either way they have a vested interest in taking a long term outlook.

I 100% agree, but this is my machine, not a dedicated mining rig, therefor there is no costs involved with it as pertains to mining, I am going to have the machine no matter if I mine or not, so only the energy costs are extra.  Also the opportunity costs are very trivial, they are much easier to estimate than any 'value' associated with bitcoins.

Gameover you have it all wrong. I couldn't agree more with grndzero.

Cost of producing a bitcoin is as relevant to its value as the value of paper the dollar or euro are printed on is to their value.

I'm very new to bitcoin. What brought me here is not speculation but the realization that this is an awesome way to transact.

The future life and future value of bitcoin will entirely depend on whether there will be demand for it to buy and sell stuff.

It is this demand that will make or break BTC. Is BTC easy to transact? Is it easy to tranfer? Is it cheaper to keep? Is it more secure to keep than other payment means? How many products / services will there be to accept BTC? Will it be easy to exchange with "regular" currencies at will? At what cost? These are the parameters that will determine its value and not cost of electricity, h/w cost or internet connectivity costs.

By the few things I have learned so far about BTC, it looks like we have a paradigm changing transaction token in our hands and its value may very well climb drastically in the long run.

If you take this outlook, mining could be profitable as long as you don't kill your hardware by extreme overclocking or wrong cooling. If I buy a 2,000 Eu rig and don't kill it by next week then my h/w costs to produce coins are not the full 2k but the depreciating value over time.

there sure is some kind of link: who would buy something that he could produce for less? the rise of the bitcoin price is limited by the rise of mining cost.

to sum it up in a very simple to understand way....

Mining  = long term gamble...
Buying = short term gamble....

Mining you need to hope the value doesn't go down and also pay your investment off before it goes down, could take months, in this time the bitcoin system could crash or it could rise, but as we have seen the current rate was produced from a  "bubble" meaning it wont stay at these rates, which also means it will take alot longer to pay off the hardware, which also means your a more exposed to loosing due to the time frame if it goes bust..

Buying is a quick way to make money and has less risk on what you invest, but it is also exposed to the market going down, but the benifit is you can redeem your money back very quick before it goes totally down thus not loosing all of your investment.

These are the cold hard facts and thats without talking about the fact the difficulty will not drop(why should it when miners have already paid off the investment and still makes a small profit after running expenses). Leaving it to only get harder to mine which leaves you gambling on your investment longer...

For anyone just getting into it I suggest buying bitcoins as its safer and faster to make more money...

Of course, if *you* have already bought mining hardware, it would be very convenient for you to dissuade others from mining and keep the difficulty low, so *you* can pay off your hardware.

From a network point of view, higher difficulty means the bitcoin network is much more secure and resistant to attack.

Depends on electrical cost and the efficiency of your rig.  If you pay a high electrical cost, FPGAs are likely the way to go for now.  If your electrical cost is very low, GPU-rigs are still good because, relative to FPGAs, they give you more bang for your buck, at least right now.

Keep in mind, mining Bitcoins is like buying them indirectly instead of buying them directly, except that you hedge your investment in the form of your hardware.  With an efficient rig, you will pay off your hardware in less than a year and then anything after that is profit, PLUS you still have the value of the hardware itself.

All things to consider.  My advice would be to look for common trends -- a lot of very smart people are throwing down insane amounts of money on Bitcoin rigs ($100,000+ in some cases).  The new trend right now is the FPGA-based rig as well as the BFL singles and mini-rigs.

If you have the money, nothing beats a mini-rig right now.

$1000 invested in GPUs today will get you about 1 BTC per day.  If you get free electricity, they should pay for themselves (at current difficulty and exchange rate) around November.  FPGA devices will have longer payoff times (assuming difficulty and exchange rate cooperate), but are better if you pay for electricity.

If you love bitcoin and have some spare cash, build a rig and run it, and don't worry about profit.

If you are looking for a longshot investment, build a rig.

If you are looking for a sure profit, I wouldn't bother.

THREAD NECROMANCY!

Still seems like these comments apply pretty well though.  Now if only we could get back to last June's prices ;)

Not if Vlad's supposed business venture gets operational in the coming months ;)

Even with cheap or free electricity, GPU rigs don't seem to make as much sense as FPGA's.  Unless your buying used hardware of course, but I like warranties.  A BFL single will get around 1.38Mhash/$, the minirig around 1.65Mhash/$ and if you already have rigs running they don't require additional hardware.  Try and build a GPU rig from Amazon.com or Newegg.com with those numbers. I'd stick with FPGA's.

GPUs still have that well beat if you buy slightly lower end new GPUs like powercolor 6770s or something like that for around 80$ @ 200Mhash/s that gives you 2.5Mhash/$ minus power though. Undervolted but still OCed they pull around 80W.

GPUs still have fpgas beat in terms of resale value etc but long term fpgas will win a pure mining race due to the lower power costs.

Atm I'd say that if you want flexible go for GPUs but for long terms mining/other sha256 (some of the fpga boards sold atm aren't really adaptable for other purposes) go for fpga.

The only reason GPUs have become the de facto mining hardware is because FPGA/ASIC miners didn't exist back then. I foresee them going the way of the dinosaur, although not anytime soon of course.

You still have to add in the cost of additional hardware.  MB, PSU, RAM, CPU, HD or USB, PCIe extenders, frame hardware. 

Shouldn't be more than about $200 per rig, or $50 to $70 per video card.  Even less if you already have some or all of the stuff lying around.

Atm that is doable for roughly 35-40$ per gpu slot if averaged out using 1-7 extenders so yup there are additional costs fpgas still need supporting hardware as well though but that can be done at much lower levels.

The one thing that worries me about most to the fpga tech available though is the inflexibility of more or less all of the current boards barring the Icarus board. Atm I'd stay well clear of any of the fpga solutions due to their in-adaptability barring again the Icarus board (I'm attempting to order a few atm).

Given bitcoin's current level of adoption etc I'm far from certain that investing in 100% dedicated mining hardware (as in it can't be used for other purposes) is a sane investment.

Build me an order for a 6 GPU rig that beats 1.4Mhash/$ (excluding frame) and I'll send you 3BTC.  5BTC if you can beat 1.65Mhash/$. With links and items available to ship - and don't put me in rebate hell.

EDIT: paid (https://blockchain.info/tx-index/3860226/d02f27676f694826ca7feddc9ed8dd660750dc3813be9c15b42ed74a6d301b6a)

Show me an FPGA under the same conditions. :)

Doesn't exist, never said it did. 

My last two rigs purchased are as follows.

5x 5830 @ $110
Antec TPQ-1200 @ $219
MSI 890FXA-GD70 @ $180
2x2GB DDR3 $20(split between 2 rigs)
4GB USB   $5
Sempron 145 $40
Wire rack @ Target $10


Ends up around 1.52 MH/$. I bought my board for ~$120 open-boxed at Newegg. The last bulk buy of 5830s I pulled in on eBay averaged around $110. Plan on the next order being around $100 or lower. Pulls in just over 1500 MH/s and pulls around 800w.

Edit: I should note, I know this isn't a 6 GPU rig but 6 GPU didn't make sense. Also, I forgot to include the three PCIe extenders I used at $5/pop. So, in the end it is around 1.50 MH/$.

1x refurbed mobo: http://item.taobao.com/item.htm?id=14015663301 (http://item.taobao.com/item.htm?id=14015663301) 698.00 CNY   =   110.649 USD

6x extenders http://item.taobao.com/item.htm?id=3607685593 (http://item.taobao.com/item.htm?id=3607685593) and http://item.taobao.com/item.htm?id=14360247848 (http://item.taobao.com/item.htm?id=14360247848) 15.00 CNY   =   2.37784 USD x6 = 14.27 USD

cpu sempron http://item.taobao.com/item.htm?id=13360385486 (http://item.taobao.com/item.htm?id=13360385486) 130.00 CNY   =   20.6083 USD

2 gb ddr3 http://item.taobao.com/item.htm?id=6666425787 (http://item.taobao.com/item.htm?id=6666425787) 63.00 CNY   =   9.98693 USD

1 PSU kinda shitty but usable http://item.taobao.com/item.htm?id=13444136885 (http://item.taobao.com/item.htm?id=13444136885) 300.00 CNY   =   47.5615 USD

6x 6770 http://item.taobao.com/item.htm?id=16091076299 (http://item.taobao.com/item.htm?id=16091076299) 420.00 CNY   =   66.5606 USD =  399.3636 USD

2x molex-pci-e adapters http://item.taobao.com/item.htm?id=1131318398 (http://item.taobao.com/item.htm?id=1131318398) 2.50 CNY   =   0.396302 USD = 0.8 USD

Total= 603.23933 USD

Hash 6x 200Mhash/s

1.98926 $/Mhash

Most 6770s will do around 210 Mhash/s I only have 2 of the ones in the link they do 204-206 which is ok when comparing with 5770s so the actual number should be closer to 2$/Mhash

Should the PSU be on the shitty side http://item.taobao.com/item.htm?id=15685788419 (http://item.taobao.com/item.htm?id=15685788419) is available @ 320.00 CNY   =   50.7221 USD or http://item.taobao.com/item.htm?id=14101614506 (http://item.taobao.com/item.htm?id=14101614506) 328.00 CNY   =   51.9894 USD

Still leaving the overall price way nicer than 1.65Mhash/$

1EXS3q5XhbL5iUKCNCwYg6q4sgJEhmftUP

And whats my cost for a translator and shipping put it at  ???

Person C) Already owns a same kind of computer, games with it, won't sell it, and realizes "holy crap, you mean I can make real money letting my already kick-ass video card do some work while I'm at work or sleeping?  And then I can use these magical coins to buy an even better video card or parts for even better gaming?  And then continue (nearly) ad infinitum?"    :)

I actually spent $3000 on a desktop computer that I use for mining.  While it only pulls 1.35 G/Hash, I'll be able to sell this thing in 3-4 years for around $1500 easily.  It's one badass mofo machine, and all the parts are covered under warranty for 4 years.

In other words, free kick ass machine!!!  I can mine BTC and LTC with it, watch a movie, and use professional recording software to record my music all at the same time   :D

When I have used one, the shipping was the killer.  It was nearly 50% of the product price.  Ordering things like ram, cpu's, HDs do not make sense for US buyers from taoboa.  Cables, 'brand name' clothing,  component level items like raw chips and other things on the other hand can be a bargain even with high shipping.

That wasn't stated anywhere in your original challenge:


And if you're so xenophobic as to expect US or where ever you are based only replies to your posts then say so.

Oh and btw Chrome has a built in translation function that makes most of those pages more or less readable.

You'll have to find someone crazy enough to by second-hand power-hungry hardware at the same (or maybe even lower) perf/price ratio as brand new power-savvy hardware. Good luck with that, although I guess it can be found...

Cards:  6x 6870 @ ~130 ea.   =$780

https://bitcointalk.org/index.php?topic=76302.0

Sempron - 145 - $40

http://www.newegg.com/Product/Product.aspx?Item=N82E16819103888


Ram - $9

http://www.newegg.com/Product/Product.aspx?Item=N82E16820148368



Adapters - 6* $5        = $25

http://www.ebay.com/itm/New-PCI-E-Extension-Cable-1X-16X-Riser-Extender-Card-cable-/260987366239?pt=LH_DefaultDomain_0&hash=item3cc40f2b5f#ht_3612wt_754


mobo            =$145

http://www.newegg.com/Product/Product.aspx?Item=N82E16813128514&Tpk=GIGABYTE%20GA-990FXA-UD3


PSU  x2          =$180

http://ncix.com/products/?sku=63239&vpn=P1850SNLB9&manufacture=XFX


That's ~ $1179

Take an avg of 300MH/card is 1800MH/s ->  1.53MH/$
Take a max of 330MH/card is 1980MH/s  ->  1.68 MH/$

There, met your requirements.  You can do even better if you buy used, up to you..

Since my projections to beat your upper request are assuming all the cards clock well, and my lower beats your lower and assumes they all clock ok..

You can send 4 BTC whenever you're ready.  kthnx

19o5QDoEqspRm27WDgun4Dov3n6QNdNCjo

I don't.  The only difference between my list and the others proposed are:

A)  All click to order, in english, in N.A.

B)  They're all new components (except the refurb cards).   

Which are to address the two BS excuses he had about the other lists. 

One can also use smalltao.com which is what I've used in the past since I can't figure out how to purchase my babies (lol) from taobao without A) being a resident of china and B) not having a Chinese bank account/credit card.

Or you can use my btc service :)

Wow go offline for awhile and everyone gets cranky.  Sorry I didn't have access to my wallet from my phone.


Your right it wasn't stated.  I never said I wasn't paying you, I had no way of checking the information because I couldn't read it. Chrome did the job, thank you.


This is much better...

5BTC sent to each of you...I apologize for the delay.
https://blockchain.info/tx-index/3860226/d02f27676f694826ca7feddc9ed8dd660750dc3813be9c15b42ed74a6d301b6a (https://blockchain.info/tx-index/3860226/d02f27676f694826ca7feddc9ed8dd660750dc3813be9c15b42ed74a6d301b6a)

Thanks :)

Whoa, not only did you come through, but you bountied up twice!  I'm impressed. +1 to you my good man.

the 7970 gives 500 Mhash

7970 gives a lot more than that.  Mine is overclocked (on air) to 1080/950 and I'm getting about 640 MH.

And to the guy that thinks he's can sell his $3000 rig in 3-4 years for $1500, yeah, good luck with that, it's not gonna happen.  Maybe if you sell it within 12 months, but at the rate stuff is coming out now, you'll be lucky to get 25% of your original cost.  Don't believe me?

Almost exactly 4 years ago, ATI released their flagship 4870 X2 card for $559.  You can grab one now on eBay for about $140 Buy it now and some are selling as auctions for $50-$75...