Using LC0 with one or two GPUs - a guide

[Laskos]

A lill update for the guide...

- PCIe lanes
A common GPU uses 16x lanes, 8x should be sufficient with current Lc0, 4x might
have performance penalties of estimated 5%.

http://talkchess.com/forum3/viewtopic.p ... 92#p824192

- External GPU
eGPU uses commonly Thunderbolt (resp. upcoming USB4) connection with 4x PCIe
lanes, expect a est. 5% penalty with current Lc0.

- Speedup by RTX TensorCores?
Speedup by Nvidia RTX TensorCores is estimated to be about 2x compared to non
TensorCores gpus with same FP16 throughput.

http://talkchess.com/forum3/viewtopic.p ... 47#p870041

- Backends
There are different GPU backends with different releases and NPS throughput, so
might have to check recent benchmarks of recent backend versions like OpenCL,
CUDA, CUDNN, DX12. The DX12 backend should also run with upcoming Intel/AMD
GPUs on Windows OS. The OpenCL backend should also run on ARM/Mali GPUs.

--
Srdja

Thanks, goof to have these as reminder.

[corres]

For running LC0 we need big Virtual Memory that is big Windows page-file (swap-file) + physical memory (RAM).
The measure of the needed virtual memory is depend on the speed of GPU and the running time. In general ~ 100 - 150 GB page file is enough. The page file can be set on the Windows Control Panel -> System page.
Because Lc0 no need fast page file, we can use the HDD for page file too. In this mode we can spare the price of big RAM-s and expensive SSD-s.

[smatovic]

...
If you have two or more GPUs you need not only more case ventilator but bigger case - full tower - also, or
you should buy "Blower type" GPUs, what blow out the hotted air from the case.

Yes, there are radial (blower) and axial fan designs, I guess up to 250 watt TDP you can run radial with acceptable noise level to blow out the air out of the case via the rear slots, with > 250 watt it seems the tripple-axial designs prevail, or alike.

https://www.howtogeek.com/365215/what%E ... pu-cooler/

I myself prefer a custom build water cooling solution for lower noise level and core temps.

--
Srdja

[corres]

...
If you have two or more GPUs you need not only more case ventilator but bigger case - full tower - also, or
you should buy "Blower type" GPUs, what blow out the hotted air from the case.

Yes, there are radial (blower) and axial fan designs, I guess up to 250 watt TDP you can run radial with acceptable noise level to blow out the air out of the case via the rear slots, with > 250 watt it seems the tripple-axial designs prevail, or alike.

https://www.howtogeek.com/365215/what%E ... pu-cooler/

I myself prefer a custom build water cooling solution for lower noise level and core temps.

--
Srdja

Tastes and smacks...
Opposite to the cited article there is an important difference between "normal" and "blower' heating systems.
In "normal" systems the ventilators only mix the hot and cool air in the case what we should remove from the PC case but the "blower" blow out the hot air from the case of PC and from the case of GPU, too.
The water cooling system is not ideal, because pump is noisy and it needs extra place, attention and maintenance.