Benchmark Results show too many CPUs

Questions and Answers : Macintosh : Benchmark Results show too many CPUs

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Charles Michael Fulton

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Message 1119601 - Posted: 21 Jun 2011, 5:04:43 UTC

I have a 2009 Mac Pro Quad Core 2.66 ghz, which I recently purchased. When running the CPU benchmarks, BOINC identifies "8" as the number of CPUs. Not a huge deal, but I think that BOINC downloads 8 tasks and attempts to do them all at once. This results, I think, in a less-than-optimum workload for my Quad Core Mac. If it would just download 4 at a time, I think it would finish the tasks much quicker.

Has anyone else experienced this problem? Is there anyway to adjust BOINC so that it sees 4 cores instead of 8?

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Bob Merrill

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Message 1119649 - Posted: 21 Jun 2011, 9:47:22 UTC - in response to Message 1119601.

There is a place in preferences where you can set how many cores Boinc should use.


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Profile Gundolf Jahn

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Message 1119652 - Posted: 21 Jun 2011, 10:38:43 UTC - in response to Message 1119601.

You probably have turned on hyperthreading. So, BOINC correctly sees eight CPUs (four real and four virtual ones).

You can either turn hyperthreading off or, as pixzy suggested, go to your Computing preferences and set "On multiprocessors, use at most 50% of the processors".

Gruß,
Gundolf

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OzzFan
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Message 1120416 - Posted: 23 Jun 2011, 14:34:19 UTC - in response to Message 1119601.

According to Intel, your Xeon W3520 is a quad core CPU with Intel HyperThreading Technology. HyperThreading takes each physical core and makes it appear as two logical cores to get more efficient use out of the processor registers.

So in fact your 4 physical core has 8 logical cores thanks to HTT and BOINC is reading your CPU correctly.

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Todd Madson

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Message 1120688 - Posted: 24 Jun 2011, 2:18:26 UTC

You will actually get better results if you let it crunch eight.


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Charles Michael Fulton

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Message 1121761 - Posted: 26 Jun 2011, 18:38:00 UTC - in response to Message 1120688.

Good to know! Hyperthreading tech, eh? Neat!

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Questions and Answers : Macintosh : Benchmark Results show too many CPUs


 
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