So given that, what would be the optimal value for <cpu_usage>?

There are philosophies:

1) Tell BOINC to run at 100% CPU, and then use the <cpu_usage> setting to have BOINC reserve cores when GPUGrid tasks are running.

... If you are going to go this route, then the answer depends on how many CPUs you want to consider budgeted by the GPUGrid tasks. Note, that the <cpu_usage> setting doesn't control how much of the CPU gets used -- instead, the setting controls how much CPU is "considered budgeted" due to the coprocessor (GPU/ASIC) task. I'd recommend setting it to 0.5, such that, when 4 GPUGrid tasks are running, BOINC will consider 2 CPUs budgeted. If you want to, instead, budget 1 CPU per GPUGrid task, then set <cpu_usage> to 1.0, such that at "Use 100% CPU" setting, 4 threads are reserved. On a single-GPU system, 1.0 might be a good option. But on a multi-GPU system, you'd want to set <cpu_usage> to free up at least 1 core total, or more, but maybe not as many cores as GPU tasks. For me, on my 3-GPU system [1 task per GPU], I use 0.667, such that, when 3 GPUGrid tasks are running, 2 cores are reserved.

Using this approach is cleaner than option 2 below, but is a bit tedious to change, since you have to change the app_config.xml and then restart BOINC to get the UI to show the CPU usage values correctly.

2) Use the "Use X% CPUs" setting to free up threads.

...I don't prefer this option, but it does end up being handier than having to edit an app_config.xml and restart BOINC. If you go this route, then you might set <cpu_usage> to 0.001, and then, just manually control how many threads are free, by manipulating the "Use X% CPUs" setting.

Long story short: For your 4-GPU-tasks, try <cpu_usage> of 0.5 (free up 2 cores) or 0.75 (free up 3 cores) or 1.0 (free up 4 cores). If you're looking for best GPUGrid GPU performance while also doing some CPU tasks, then use 1.0.

*1124MHz

...

Thanks, Jacob. You've given me some good info and things to try with this setup.

Will give 100%, 1.0 a try based on your suggestions and see how that goes.

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My BOINC Cruncher, Minecraft Multiserver, Mobile Device Mainframe, and Home Entertainment System/Workstation: http://www.overclock.net/lists/display/view/id/4678036#

You're welcome! Nice setup, by the way -- If you're ever interested in upgrading it, I wouldn't mind a used GPU at a decent price :) I'm pretty sure my MSI Frozr II fans are failing, but I'm still running GPUGrid on it, and having the other 2 EVGA rear-exhaust fans try to compensate :) It's literally a hot mess over here - All 3 GPUs at max fan with 70-80*C, and CPU at max fan at 86*C. This office is a sauna!

CPU at max fan at 86*C. This office is a sauna!

Notes on Intel Core i7-965:
Maximum operating temperature: 67.9°C
Maximum power dissipation: 230.14 Watt
Thermal Design Power: 130 Watt

Yikes, I'm surprised it's still running. We'll keep our fingers crossed :-)

Where did you get that info?

Everything I see shows that TjMax is 100*C, and I've only ever seen it go above 90*C whenever it was loaded and the fan didn't react quick enough.

I believe my CPU is actually:
Intel® Core™ i7-965 Processor Extreme Edition
http://ark.intel.com/products/37149/Intel-Core-i7-965-Processor-Extreme-Edition-8M-Cache-3_20-GHz-6_40-GTs-Intel-QPI
... factory overclocked from 3.2 GHz to 3.74 GHz (5 years ago by Dell).

Edit:
Ah, I see on that page:
"TCase: 67.9°C"
"Case Temperature is the maximum temperature allowed at the processor Integrated Heat Spreader (IHS)."
... I think that's different than the 80*C-90*C core temps that I'm monitoring. In fact, here's a page that explains some of the differences: http://www.intel.com/support/processors/sb/CS-033342.htm

Anyway, if we need to discuss this further, send me a PM. Otherwise, we should get back to the topic "app_config.xml" :)

Just thought I'd mention it. Here's the info I saw, Intel Core i7-965 Extreme Edition:

http://www.cpu-world.com/CPUs/Core_i7/Intel-Core%20i7%20Extreme%20Edition%20I7-965%20AT80601000918AA%20(BX80601965).html

For the external CPU temp (Tcase) I try and stay below 50 to 55 degrees C, and for the core temps below about 70 to 75 degrees C. Jacob, I think your CPU's thresholds are a little higher than mine, but you're still definitely pushing it a bit more than I would care to. Might want to look into upgrading your CPU cooler, or possibly down-clocking a little. It could be the GPUs' heat causing the CPU to heat up more, so might want to look into cooling the case inside down more too. I like to keep a well defined airflow path through my case that goes with convection; cool air in from the bottom front and side, and hot air out the back and rear top. So naturally I'm also a fan of the cards that exhaust heated air out the back instead of mixing it up inside the case.

As for my cards, I've only had them a couple of months now, so I will likely be hanging onto them for some time yet. Might even pick up a couple more if they're still available and I decide to go to the X99 build (i7-5960X, ASUS X99-E WS). I'll keep you in mind though if/when it comes time for them to find a new home. I might end up passing them down to some other friends of mine, if they're in the market for them. (I usually sell them at half the current going rate of new cards.) We shall see.

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My BOINC Cruncher, Minecraft Multiserver, Mobile Device Mainframe, and Home Entertainment System/Workstation: http://www.overclock.net/lists/display/view/id/4678036#

(Would have edited my previous post, but just missed the cutoff time.)

...

Oh, by the way (and back on topic), I wanted to say that the 100%, 1.0 CPU usage settings seems to be going great so far. My only slight concern is CPU availability for other programs, but so far that doesn't seem likely to be an issue. Think I will stick with these settings for some time and see how it plays out. Thanks again.

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My BOINC Cruncher, Minecraft Multiserver, Mobile Device Mainframe, and Home Entertainment System/Workstation: http://www.overclock.net/lists/display/view/id/4678036#

Open Process Explorer to check the GPU tasks. You'll see they're really probably only using 15-25% of a core. So, by reserving 4 threads, you're actually allowing plenty of CPU to be readily available for any other tasks you might be doing (like browsing, Word, etc.). You *could* allocate that extra CPU towards CPU tasks (by using 0.001 <cpu_usage>), but then as I said, GPUGrid GPU tasks performance would suffer a bit.

It's all about tradeoffs. But Process Explorer will show you exactly how much CPU each of your acemd tasks is really using.

Yeah, not so much wondering about how much GPUGrid will use of those 4 threads, but more so some other programs I run could potentially want to load them up. (A few Minecraft servers, some games, media players, etc. all running at the same time.) But yeah, I think I should be fine. And if not, I can adjust things as needed later on. Right now I'm concentrating more on being patient enough to see how these settings play out.

Other than that though, I have noticed GPUGrid pulling in CPU tasks as well now which run on 12 CPUs. Some of those will somehow manage to run for a small fraction of a second before being suspended indefinitely (or maybe to run for another fraction of a second at some point) until I abort them. I'd rather not use up GPUGrid's bandwidth needlessly by downloading these tasks (nor get "their hopes up," thinking I'll be crunching them). Any ways for getting around this issue that you know of?

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My BOINC Cruncher, Minecraft Multiserver, Mobile Device Mainframe, and Home Entertainment System/Workstation: http://www.overclock.net/lists/display/view/id/4678036#

If you don't want certain applications from a project, go into the project's web settings and disable those applications for your account.

OK. Found the settings. Thanks.

Was thinking it was due to something I had done locally, since I hadn't noticed these tasks being pulled in before, but guess that's moot.

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My BOINC Cruncher, Minecraft Multiserver, Mobile Device Mainframe, and Home Entertainment System/Workstation: http://www.overclock.net/lists/display/view/id/4678036#

After a bit more tweaking...

I decided to dedicate my GPUs to running 2 long work units each (provided they're available), as I think this will get the most out of my hardware.

GPUs are loaded more consistently at a higher 90% to 92%, and VRAM is loaded about 56% (approaching 3.5GB) with 4 WU in each card's VRAM since they're in SLI and mirrored. Fortunately the GPUs are holding at a decent 73 to 75 C°.

The higher GPU loads seem a little strange to me, as I would have thought they would have crunched through WU more similarly regardless of their total run times. As it is, it seems there's a bit more for them to work on at any given time with the long work unites, not just in total. Then again, this may just be due to the particular WU the GPUs are currently crunching.

Anyway, long story short, it looks like this will work out to be another slight performance improvement.

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My BOINC Cruncher, Minecraft Multiserver, Mobile Device Mainframe, and Home Entertainment System/Workstation: http://www.overclock.net/lists/display/view/id/4678036#

Hi Wrend,

I sent you a PM, as the best solution/method to improve / optimize crunching on GPUGRID I've tested is here :

http://www.gpugrid.net/forum_thread.php?id=2123&nowrap=true#16832

Kind Regards,

Phil1966