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Old 2019-12-27, 16:26   #7
kriesel's Avatar
Mar 2017
US midwest

501510 Posts

Originally Posted by Runtime Error View Post
Thanks for the helpful replies!

I do not pay the electric bill for these machines, but I only get them when no one else is logged on and they haven't been taken offline (e.g. winter maintenance). Otherwise "worth it" reignites the "usefulness" conversation; I'll stay out of it. But Gordon, wow from those numbers, it seems like hunting on GPUs is cheaper than on CPUs both in upfront cost and marginal cost. Is that conclusion correct?

I've set CUDALucas up on one machine for double checks. Currently getting 29.60ms/iter on a 56M exponent. Task Manager says it's only using 10% of the GPU capacity, but perhaps that calculation is similar to how Prime95 only uses 50% due to hyperthreading. Does that sound about right?
Sounds like Windows 10. The gpu monitoring is a work in progress there, and in my opinion quite unreliable on gpu load. Try GPU-Z for continuous graphical, or nvidia-smi for very low overhead character-cell gpu stats on request. (Both have optional logging.) I usually use a tiny batch loop for nvidia-smi, so it gives me an update whenever I press a key in that command prompt box, otherwise nvidia-smi just sits idle showing the last results.
title nvidia-smi in %cd%
"c:\Program Files\NVIDIA Corporation\NVSMI\nvidia-smi.exe"
goto nv
Gpu utilization displayed is usually 95-100%. There are some exceptions to that; fast gpus running mfaktc and not yet well tuned; CUDAPm1 during gcd on a cpu core; brief periods in gpuowl during the GEC.
C:\Users\Ken\Documents>goto nv

C:\Users\Ken\Documents>"C:\Program Files\NVIDIA Corporation\NVSMI\nvidia-smi.exe
Fri Dec 27 07:39:29 2019
| NVIDIA-SMI 378.66                 Driver Version: 378.66                    |
| GPU  Name            TCC/WDDM | Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|   0  Quadro 2000        WDDM  | 0000:0F:00.0     Off |                  N/A |
|100%   83C    P0    N/A /  N/A |     85MiB /  1024MiB |     99%      Default |
|   1  GeForce GTX 106... WDDM  | 0000:28:00.0     Off |                  N/A |
| 53%   71C    P2    83W / 120W |    232MiB /  3072MiB |     99%      Default |

| Processes:                                                       GPU Memory |
|  GPU       PID  Type  Process name                               Usage      |
|    0      5860    C   ...n\My Documents\tf-q2000\mfaktc-win-64.exe N/A      |
|    1      5944    C   ...CUDALucas2.06beta-CUDA6.5-Windows-x64.exe N/A      |

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