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dual GPU question

Posted: Sun Mar 22, 2020 4:52 pm
by nathangast
New to F@H, I contributed to SETI@HOME way back 15-20 years ago.
Had about 900 pc's running SETI@Home.

I built a new monster to play games on, AMD Threadripper 1950x with 64gb and dual NVIDIA 1080TI 2 years ago.
Nothing every used the dual setup so I put 1 of them in another old AMD Ryzen 7 1800x.
I'm considering putting it back in my monster if F@H will actually utilize the second card.

TLDR:
Does F@H utilize multiple GPUs?
If YES, is there a limit?

Thanks

Re: dual GPU question

Posted: Sun Mar 22, 2020 4:58 pm
by HaloJones
it will use both but individually rather than together.

Re: dual GPU question

Posted: Sun Mar 22, 2020 5:38 pm
by JimboPalmer
And the limit is usually the number of PCIE channels, frequently a mother board with two GPUs will run both at x8, by 4 GPUs you are down to x4

with fewer channels you spend more time feeding data into the card, and so less time folding. Oddly Linux is much better at this than Windows, so if you run multiple cards, Linux looks better and better.

Re: dual GPU question

Posted: Sun Mar 22, 2020 5:50 pm
by Nathan_P
JimboPalmer wrote:And the limit is usually the number of PCIE channels, frequently a mother board with two GPUs will run both at x8, by 4 GPUs you are down to x4

with fewer channels you spend more time feeding data into the card, and so less time folding. Oddly Linux is much better at this than Windows, so if you run multiple cards, Linux looks better and better.


Only with mainstream hardware, Threadripper has enough lanes to run dual or even triple x16.