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Old 2015-10-15, 06:17   #1
LingUaan
 
Oct 2015

23 Posts
Default Strange behaviour of Prime95

Prime95 needs 0.080s and 0.072s per iteration respectivly on my System.
After starting Firefox performance increases to: 0.068s and 0.060s per iteration respectivly.
An improvement of about 15%.
I stumbled upon this by pure accident and couldn't believe it at first.
But I duplicated this behaviour several times.
I don't know what difference Firefox makes but someone should figure it out and add it to Prime95.
At first glance this performance increase seems to be a low hanging fruit.
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Old 2015-10-15, 09:43   #2
axn
 
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CPU and OS version?
RAM type and speed, and how much RAM is installed?
Version of P95?
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Old 2015-10-15, 09:51   #3
retina
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I expect this is some kind of clocking difference. Perhaps the OS is going into a lower power mode when only low priority tasks are running.
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Old 2015-10-15, 11:59   #4
LingUaan
 
Oct 2015

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Quote:
Originally Posted by axn View Post
CPU and OS version?
RAM type and speed, and how much RAM is installed?
Version of P95?
OS = W7 Ultimate and it doesn't go to a lower power mode at times.
P95 = V28.5 Build 2
GPU = Radeon HD 7770 with mfakto 0.14 running, but this has no effect on the CPU

I tried also IE and Opera but the described effect happens with Firefox only.
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Old 2015-10-15, 12:02   #5
LingUaan
 
Oct 2015

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Unhappy

Forgot the pictures.
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Old 2015-10-15, 12:02   #6
retina
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Does CPU-Z show any changes in the clocking of the RAM or CPU with/without FF running?
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Old 2015-10-15, 12:05   #7
LingUaan
 
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And the last one.
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Old 2015-10-15, 12:14   #8
LingUaan
 
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Quote:
Originally Posted by retina View Post
Does CPU-Z show any changes in the clocking of the RAM or CPU with/without FF running?
No changes at all, but Iteratin time goes up instantly.
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Old 2015-10-15, 12:22   #9
LingUaan
 
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I wonder if I'm the only one to see this strange though welcome behavior.
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Old 2015-10-15, 14:19   #10
axn
 
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Hypothesis: P95 is unable to correctly identify which virtual HT cores correspond to which physical core. Running FF somehow moves the threads over to correct pairs.

Can you post P95 log regarding how the virtual cores pair up? (Exiting and restarting P95 will show the details).

EDIT:- Is your mfakto instance(s) using CPU sieve or GPU sieve?

Last fiddled with by axn on 2015-10-15 at 14:21
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Old 2015-10-15, 14:52   #11
LingUaan
 
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Here the requested details of CPU pairing.
One instance of mfakto and it sieves on GPU.
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