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World Community Grid Forums
Category: Support
Forum: GPU Support Forum
Thread: 16 threads on one 7950 |
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Thread Status: Active Total posts in this thread: 8
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B2I
Senior Cruncher usa Joined: Jan 23, 2011 Post Count: 232 Status: Offline Project Badges: 
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As an experment in extremes, I set my 7950, 2600 (nonK), H61 MB app_info to count.0625 and a ncpu to .5. It is happily running the 16 threads with 100% CPU useage. Only time will tell if it is stable and puts out good data, AND ups its PPD. Just wondering if anyone else has tried this
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OldChap
Veteran Cruncher UK Joined: Jun 5, 2009 Post Count: 978 Status: Offline Project Badges: 
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Certainly have, I found that at 1100 on my asus card running on my 3770K @4.8 there was a need to bump the GPU volts a little to stop the errors and invalids that would show up occasionally (<1%) but since doing so all is well.
----------------------------------------A generalisation from me would be that ppd is not much affected because (and this is a guess) the additional time lost through more switching between wu's during processing is offset by better separation of the wu's in running. Also, faster running caused by better separation means lesser points claimed/awarded..... but that is just the old make it do more and you get less conundrum. This setup is running around 880K ppd  [Edit 1 times, last edit by OldChap at Dec 8, 2012 3:53:30 PM] |
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BladeD
Ace Cruncher USA Joined: Nov 17, 2004 Post Count: 28976 Status: Offline Project Badges: 
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Can't top that!
----------------------------------------But since I run out of HCC GPU WUs earlier, POEM started on my 7870 (6 WUs). When I started getting HCC WUs again, I paused 3 POEM WUs and 4 HCC WUs started! So ATM, I'm running 3 POEM WUs and 4 HCC WUs on my 7870 with 2 SETi CPU WUs on my i7. |
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B2I
Senior Cruncher usa Joined: Jan 23, 2011 Post Count: 232 Status: Offline Project Badges:
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Thanks for the quick replies. I did a quick check and the CPU has settled into nice consistent use patten slowly changing between a low of 75% and a high of 98%. MSI afterburner reports GPU usage as an almost flat line at 98-99 percent. Temps on the GPU are running almost a flat 50C with 50% fan in a cool room of 65-68 F. I'll report back on PPD and errors when I get a couple days of data.
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
It should be fine. I have been running 20 units on each of my 7870 and 7970 with only the rare error here and there (not even 1 per day on those cards).
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Former Member
Cruncher Joined: May 22, 2018 Post Count: 0 Status: Offline |
The contra productive is a known phenomena... at some point the system housekeeping takes so much time, that production per unit of time actually drops, rather than increases. Long as the ppd goes up and valids continue, you're fine [WCGDAWS is an excellent tool to filter on dates completed/science, so returned work can later be matched to granted credit].
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Hypernova
Master Cruncher Audaces Fortuna Juvat ! Vaud - Switzerland Joined: Dec 16, 2008 Post Count: 1908 Status: Offline Project Badges:
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Thanks for the quick replies. I did a quick check and the CPU has settled into nice consistent use patten slowly changing between a low of 75% and a high of 98%. MSI afterburner reports GPU usage as an almost flat line at 98-99 percent. Temps on the GPU are running almost a flat 50C with 50% fan in a cool room of 65-68 F. I'll report back on PPD and errors when I get a couple days of data. B2I My personal experience with a 7970 board is that it all depends what you are trying to maximize. If it is runtime, then go for as many threads you can. If it is WorkUnits and consequently points then you aim the maximum value. Running 10 GPU threads and 12 CPU (on a 12 thread CPU) I get over 2'000 WU per day or over 1 Million points. Running 16 GPU threads and 24 CPU threads I get around 1'750 WUs, so much lower in fact. The reason is a major slowdown of the CPU crunching capability. If the CPU share of work would be much reduced we could even pull more from the same board. AT this time the CPU is still playing an important role. If you have a dual socket system with 2 CPUs I wonder if we could then better use the GPU threads. But can two CPUs share the same GPU efficiently ?  |
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Bearcat
Master Cruncher USA Joined: Jan 6, 2007 Post Count: 2803 Status: Offline Project Badges:
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I bumped mine to 12 on my dual socket hex. Takes about 11 to 12 minutes with an occasional 9 to 10 minutes. Now at 10, completing at around 8 minutes. The bottleneck is the GPU when increasing # of GPU wu's. Maybe the 8000 series will change that.
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Crunching for humanity since 2007!
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