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Old 2009-07-30, 00:54   #1
Primeinator
 
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"Kyle"
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Default Prime95 PM Slowdown?

Hello,

I've been noticing for some time that Prime95 25.9 has been slowing down in the nighttime hours and early morning by a considerable amount. I am running two LL tests in the 45M range on a Core 2 Duo 2.0Ghz.

During the day, the LL test usually paces at about .098 to .1 seconds per iteration. However, during the night this slows to from .11 to .14 seconds per iteration. Note- nothing else is running on my computer. I figured that a night or two would could be dismissed as an anomaly, but this has been happening for weeks. Any ideas on what is wrong?

Thanks.
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Old 2009-07-30, 01:12   #2
cheesehead
 
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Quote:
Originally Posted by Primeinator View Post
During the day, the LL test usually paces at about .098 to .1 seconds per iteration. However, during the night this slows to from .11 to .14 seconds per iteration. Note- nothing else is running on my computer.
The first thing I'd do would be to question the last item. If you've already tried monitoring the system for other tasks running during the times of slowdown, and found nothing, then I'd suspect a malware infection.
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Old 2009-07-30, 05:03   #3
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Before thinking of malware I would think of anti-malware : antivirus programs for instance. Take MS Forefront : is a resource hog and will use more than three CPU hour in a workday for updates and "quick" scans.

Jacob
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Old 2009-07-30, 05:55   #4
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Another known pig is defrag software. But that should only run 1 time a week.
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Old 2009-07-30, 06:23   #5
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Quote:
Originally Posted by S485122 View Post
Before thinking of malware I would think of anti-malware : antivirus programs for instance. Take MS Forefront : is a resource hog and will use more than three CPU hour in a workday for updates and "quick" scans.
Quote:
Originally Posted by Uncwilly View Post
Another known pig is defrag software. But that should only run 1 time a week.
... and in either case, legitimate software would have shown up on a system monitor listing active tasks. So if there's already been a check for other tasks that came up empty, malware is the next suspect.

Last fiddled with by cheesehead on 2009-07-30 at 06:24
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Old 2009-08-01, 14:23   #6
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Sorry, I have been away for a while. Spyware was the first thing that I checked- AVG 8.5 Free declared my computer spyware and virus free.

The only thing I can think of (that is probably wrong) is that somehow my Prime95 memory settings (which are much higher at night) are affecting the LL and confusing the test somehow, even though LL's do not use that much memory. This is probably a wrong idea, but it's the only one I can think of.
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Old 2009-08-02, 10:19   #7
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Quote:
Originally Posted by Primeinator View Post
Sorry, I have been away for a while. Spyware was the first thing that I checked- AVG 8.5 Free declared my computer spyware and virus free.
That's nice, but does AVG absolutely guarantee that it will find 100% of malware? Probably not.

Quote:
The only thing I can think of (that is probably wrong) is that somehow my Prime95 memory settings (which are much higher at night) are affecting the LL and confusing the test somehow, even though LL's do not use that much memory. This is probably a wrong idea,
Yes.

Quote:
but it's the only one I can think of.
I've had malware infections that were completely undetected in scans by major-brand antivirus/antispyware. Cure: Wipe the software disk and reinstall Windows XP.

Because of the reliable repeatability of LL iterations, I recommend that persistent unexplained timing discrepancies such as you report should be considered suspicious, possible evidence of malware, until proven otherwise.
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Old 2009-08-02, 21:29   #8
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It might be as simple as AVG running its daily scan in the early hours of the morning.
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Old 2009-08-02, 22:10   #9
Primeinator
 
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Quote:
Originally Posted by cheesehead View Post
That's nice, but does AVG absolutely guarantee that it will find 100% of malware? Probably not.

I've had malware infections that were completely undetected in scans by major-brand antivirus/antispyware. Cure: Wipe the software disk and reinstall Windows XP.

Because of the reliable repeatability of LL iterations, I recommend that persistent unexplained timing discrepancies such as you report should be considered suspicious, possible evidence of malware, until proven otherwise.
I have Vista, but the process would be the same. That's fairly drastic, don't you think? Is there a simpler alternative?

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It might be as simple as AVG running its daily scan in the early hours of the morning.
No. I have modified the settings of AVG to run only once a week.
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Old 2009-08-02, 22:49   #10
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Quote:
Originally Posted by Primeinator View Post
I have Vista, but the process would be the same. That's fairly drastic, don't you think? Is there a simpler alternative?
Sure. Live with the problem.

I didn't tell you to wipe your disk and re-install. I said that was the cure in a case I had.

I'm not declaring that malware must be what's happening in your case. I'm saying that you haven't ruled it out with the measures you've reported so far.
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Old 2009-08-03, 11:06   #11
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You can do some performance monitoring with the normal windows tools ... I think you can find it under adminstrative tools.

Check after a day what process are stealing your processor cycles.
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