http://forums.nvidia.com/index.php?showtopic=97478 claims differently. I have no first hand experience, so I can't say directly, but I see noe reason why windows would set such a limit.

/agreed as to possibly destroying the FSB though. Consider an externally powered PCI-E riser or something.

not all cards are happy at that rate. Just out of curiousity I bumped a card from 975/300 to 1000/185 and my mhash dropped from 432 to 398.

Yes, whatever your card has to actively display takes power away from mining. If you watch a movie or whatever some of the GPU cycles goes there instead. I'm somewhat surprised at losing quite so much hashing power. Perhaps turn off windows aero or whatever all those fancy pants addons are.

iirc stock speeds for a 5850 is 725. Just because temps are low doesn't mean the card is happy, and 225MHz (31%) overclock is quite large. Overclocking stresses hardware even at lower temps, but it shouldn't kill it in the next few days if that's what you're worried about.

Just a note, 6990s have terrible MHash/$ ratio, and the more time passes the higher the difficulty gets, making time to ROI get longer and longer.

That's too bad that you can't find it. I remember seeing cypherfox's thread for weeks with lots of bold claims and tons of people going on and on with pie in the sky dreams, but I never saw any hard evidence that he produced anything real. Would have been nice to see if that had really come to anything or not.

I'll have to look up ArtForz separately.

A single water cooling solution? Not sure what you mean by that. 8x 6990s will put off about 3000Watts of waste heat. Even a 480 radiator can't handle that. With 18 push/pull 3000RPM high static pressure fans on each, maybe 3 GTX360s could handle it (at ~10C delta).

Water cooling for mining isnt' a very cost effective way to go anyway though. Would be cheaper to build 4 rigs running 2x 6990s, and cool probably about the same (each 6990 waterblock is ~$150).

Do those even exist? I haven't been paying much attention but last I saw there wasn't any evidence of those existing.

You know what's even harsher than not fitting on the motherboard? The fact that the power draw for 7x 6990s is about 2,500Watts, which is greater than any single PSU can handle, and also draws more amps than any single household circuit can provide, let alone the power through the motherboard would almost definitely destroy it. Doomed from the outset.

I agree and disagree. For a formalized study of the differences between the two I would say yes. But I was mostly suggesting a simple pattern seeking "once over" of his history to start. Deepbit solves around 75-90 blocks a day depending on its luck, which is a sizable number to work with. He is thinking he sees ~10% difference between the two miners, which is a significant difference. Were he to look at all the points from each he should see a significant and consistent shift upward between the two data sets. As well as a significantly different average once outliers are thrown away.

To really get into the meat of the matter though I agree you need to go big on your datapoints.

This was a wholly theoretical exercise in mining vs buying as a response to someone. I chose numbers to most benefit my argument, and I said so from the start. However it was pretty close so as to be relevant, there is no point in taking shipping / building time into account, as the idea was to begin mining on the same date as buying coins, not start buying equipment. The chances of DoA equipment is irrelevant. DoA rates are negligble. I've been continually buying 5870s for < $180 for the past month, there was a sale from newegg about 2 or 3 months ago for 5870 2GB models for $180. It's not at all that much of a stretch. A 5870 gets between 430 - 440MHash/sec right now with BFI_INT and phatk, 400Mhash with a good overclock is reasonable. 2000Watts (per hour doesnt mean anything) is overkill on electricty. I run 3x5870s on < 600Watts right now overclocked, so my numbers were fine.

Anyway, small things aside, the soundness of the argument stands. When bitcoins price remains relatively stable, difficulty does not increase that much, and mining is superior to buying coins. When bitcoins price explodes obviously having bought a coin the day before is better. But no one can know the future.

As Litt says, he wishes he had bought a buncha coins instead of buying mining equipment. Why didn't he? Because he couldn't predict the future. No one knew that bitcoin was going to explode from $1 / BTC to $11 / BTC in a matter of 2 months. It might have stagnated forever. And it might continue to rise or it might plummet like a rock, in which case buying coins is far far far stupider than buying mining equipment.


My only argument from the start has been that you don't know the future, so speculating that one approach or the other is better is irrelevant. You can guess as to what you think might happen, and plan accordingly, and that's the best you can do. But don't tell people that it will definitely be this way or that.

10 days of runtime on a few cards is an incredibly poor sampling to draw from for statistical analysis. Heat is a proven killer of hardware, no ifs ands or buts about it, the rate varies however.

In all likelihood the cards will still last for a few years even running quite hot 24/7, but you certainly increase the chance of hardware degradation and failure, and the rate at which it heads to that. The MTBF is likely the length of the original warranty on the card, estimate perhaps 10-30% shaved off that.

So many threads without any criteria to be met. What do you want? To maximize profit? To minimize noise and heat? To maximize your e-peen?

If you want to make the most money I suggest you check http://www.psychic-forum.com/forum/ instead. Minimizing noise and heat would behoove you to build another rig to keep cards spaced out and happy. Maximizing epeen definitely entails lots of 6990s.

If I had $10,000 I'd buy $10,000 worth of bitcoins and then send them to 1KtzPMokNekE5pjzqaDsdf6fEr77Utn3eA

Just sayin...

You can sell it for as much as people are willing to pay for it. Law of economics.

I personally would pay like < $140 for one, but I've seen people pay upwards of $200 on these forums. Madness knows no bounds.

Were you crossfiring the cards? Or in Windows XP 32bit (I think). Crossfire is forced to 4 GPUs max. One version of windows is reported to also have that limitation.


As for PSU problem, 6 5870s can run comfortably on a 1200W with no worries. The biggest worry is still as I said frying the motherboard by running so much power through it.

Read the like 4 threads on this topic on the first page of this forum.

Your calculations are flawed in that the price is highly unstable, the difficulty is highly unstable, and mining bitcoins itself is highly unstable (the amount varies by luck, even in big pools).

What is your criteria for problems? Running a card at 100% usage 24/7 will almost certainly degrade the card. Now if it degrades its useful lifespan from 6 years to 4 years, that's not a real problem for most people, but there's no way to know any of that in advance.

Basically you are murdering your card, but you are doing it slowly. Figure out for yourself what that means to you.

I got his meaning just fine, I don't think you get my meaning.

1) Cypress chips are not to my knowledge being fabricated anymore. I don't suspect any group is just sitting on a big fat stockpile of unused Cypress chips, so in order to start a new line either AMD would need to return to a last gen fabrication line or have some stockpile to be bought out.

2) A PCB design process costs a lot of money. I'm not an electrical engineer and I'm guessing none of the rest of us are either, but talk to one and they will tell you that it's not a simple matter of slapping a chip onto a piece of silicon to make a functional graphics card. Where is the profit motive?

3) Cypress cards already sell very very well. What is the profit motive to instead of running their already existing designs, creating a custom designed PCB? As already stated there are maybe 20,000 high end cards mining right now maximum, that may seem like a big number to you, but to companies that deal with shipping out millions of units that's a waste of money.

I meant more his calculations for profitability.