GPU LL Testing FAQ

[TheJudger]

Brain: For mfaktc you can add/modify this:

"Compilable with: CUDA Toolkit 4.0, 4.1": you can add CUDA Toolkit 3.x to this list, too. I've provided executables with CUDA 4.0 and 4.1 but the source should work with 3.x, too.

"GIMPS score estim.: roughly 75 GHz days/day on GTX 560 Ti & 1 CPU core" you could add that this is limited by CPU and the GPU is sitting idle half of the time.

Oliver

[ET_]

Originally Posted by TheJudger

Brain: For mfaktc you can add/modify this:

"Compilable with: CUDA Toolkit 4.0, 4.1": you can add CUDA Toolkit 3.x to this list, too. I've provided executables with CUDA 4.0 and 4.1 but the source should work with 3.x, too.

"GIMPS score estim.: roughly 75 GHz days/day on GTX 560 Ti & 1 CPU core" you could add that this is limited by CPU and the GPU is sitting idle half of the time.

Oliver

Oliver, as GTX 600 will come out soon, with a 3x speedup, you'd better think about a way to use some spare GPU processors for sieving...

Luigi

[TheJudger]

Originally Posted by ET_

Oliver, as GTX 600 will come out soon, with a 3x speedup, you'd better think about a way to use some spare GPU processors for sieving...

Luigi

Or keep it as it is and force GTX 6xx users to run LL on GPU

Oliver

[Brain]

Originally Posted by TheJudger

"GIMPS score estim.: roughly 75 GHz days/day on GTX 560 Ti & 1 CPU core" you could add that this is limited by CPU and the GPU is sitting idle half of the time.

Oliver

My setting: I saturate my CPU with Prime95 and the GPU with CUDALucas. Additionally, I run mfaktc on top.
If I understand you correctly, given no other GPU load, you generally recommend running 2 instances? CPU-GPU-tick-tock?
I know that 1 single instance is not saturating a modern GPU.

I attached the CUDA 3.x info:

GIMPS GPU Computing Cheat Sheet (pdf)

[bcp19]

Originally Posted by TheJudger

Brain: For mfaktc you can add/modify this:

"Compilable with: CUDA Toolkit 4.0, 4.1": you can add CUDA Toolkit 3.x to this list, too. I've provided executables with CUDA 4.0 and 4.1 but the source should work with 3.x, too.

"GIMPS score estim.: roughly 75 GHz days/day on GTX 560 Ti & 1 CPU core" you could add that this is limited by CPU and the GPU is sitting idle half of the time.

Oliver

That depends on the speed of the CPU, I only use 1 core on my 560 which is powered by a 4.3 GHz 2500K and it is around 140-150 GHzD/D and 92-95% GPU load.

[Karl M Johnson]

Great pdf doc with everything in one place, one correction though:
CUDALucas does not support multi-gpu in CUDA terminology. You may be able to run N different instances on N different GPUs, but you may not run one instance on N GPUs - that's exactly what multi-gpu means.

[Brain]

Originally Posted by Karl M Johnson

Great pdf doc with everything in one place, one correction though:
CUDALucas does not support multi-gpu in CUDA terminology. You may be able to run N different instances on N different GPUs, but you may not run one instance on N GPUs - that's exactly what multi-gpu means.

Integrated.

Changes:
- CUDALucas 1.48 max exponent
- Multi GPU hint
- Minor structure and text changes

GIMPS GPU Computing Cheat Sheet (pdf)

[Brain]

CUDALucas 1.64 integrated

GIMPS GPU Computing Cheat Sheet (pdf)

[flashjh]

I live in a fairly cool part of the country and I started GPU TF and LL in the winter. Never had a cooling issue, until today.

Temps got to 61F degrees outside and my system shutdown twice. It's not the CPU causing all the heat, it's the dual 580s

I have the cover off, big fan cooling it now, but that isn't going to cut it in the summer.

My question is, what do you all do to keep your systems cool? I'm not even overclocking...

Thanks

[Dubslow]

I'd say either your cards are in a case with absolutely no airflow, or their heatsinks/fans are really really bad. The 460 I have has good enough cooling (stock cooling from mfctr) that even at full load in 80F rooms, it rarely gets above 65C.

I can imagine they cause a lot of heat (their power draw is massive) but either the fans are broken, or after the fans dump the heat it goes nowhere. What temperatures did you see them get up to?

[kladner]

Originally Posted by flashjh

I have the cover off, big fan cooling it now, but that isn't going to cut it in the summer.

My question is, what do you all do to keep your systems cool? I'm not even overclocking...

Thanks

First, I'm not dealing with that kind of firepower. But the first question is, what, and where are the intake and exhaust fans on your case? If you can get a look at them, get the brand and model. Find out their rated air flow. It is common for there to be an intake fan at the bottom front of the case (assuming a tower.) Since adapter cards are in the lower part of the case, they may be in a pretty direct line with that fan. One hopes that it is at least a 120mm. In general, cases tend to have a front-to-back air flow. If you can ramp that up, it can help a good bit. One part of that is to increase the intake CFM. Assuming a 120mm fan, see if a 38mm thick fan will fit there, and get the highest RPM you can live with on a noise basis. Here is an extreme example (not in stock).
http://www.coolerguys.com/840556090687.html
and another that is in stock:
http://www.coolerguys.com/840556021698.html

Note: I could not live with these monsters. 60++ db. But they really move air.

Then you need to think about getting air out. Preferably, you'd be pulling it out from the immediate vicinity of the video cards. Hence, slot exhaust coolers like this:
http://www.coolerguys.com/840556090755.html

The question is, can you fit something like this in when you already have two, two (or 3?!?) slot video cards in there. If not, side cover off with a 12" High Velocity floor fan blasting right in between the cards may actually be your best bet. Or, you can cut a hole in the side panel and mount a 120mm or 140mm fan there. This approach might need some experimentation to find whether blowing in or out works better.

At some point, having two major heat producers down in a corner of the case just points out the limitations of standard case ventilation. Visualize air flow, and be aware of dead air heat pockets.

Xyzzy has referred to the Very Loud boxes he runs. I'm sure he can offer some suggestions.