GPU impact on bigadv

littlepuppy · 25 Aug 2010 at 15:06

Guys, going to be adding 3, maybe 4 GTX460's to a 980x

What impact (if any) will this have on my bigadv frame time, currently circa 21 mins..

Biffa · 25 Aug 2010 at 17:03

Yes it will have an impact, a significant one in my experience.

Not had any experience with the 6 core 980X but on a i7 920 oc'ed to 4.0Ghz it effectively made bigadv unworkable, from around 30K PPD down to around 10KPPD

It could be the 6 core 980x will handle it better not sure. I found it less painful to run the regular A3 WUs for around 12/14K PPD with the gpu's running.

You also get a hit on the GPU's

You can try all sorts of tools to allocate certain cores for GPU processing and others for CPU etc.. its all good fun and all, and is a bit hit and miss whether it works or not.

Be interesting to see your results

littlepuppy · 25 Aug 2010 at 17:08

Hmmmmm, my alternative is to have a 980x just doing bigadv and then a lower "cpu" and undervolted CPU just running the GPU's...

miniyazz · 25 Aug 2010 at 17:37

If you set bigadv to use -smp 11 or 10 I would've thought it'd be fine without major PPD loss. It's when it's set to use all threads and because it's not truly multithreaded (or something) it drags all threads down to the efficiency of the least-used thread. Give the GPU a thread free and PPD stays high.

Biffa · 25 Aug 2010 at 17:54

I'd try it first before worrying too much.