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Old 2003-12-12, 12:28   #1
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Default How do I lower Prime95's CPU Usage?

See I don't really want my computer running at 100% all the time but maybe around 70%-80%, is there a way to make Prime95 not make my computer run at 100%??
 
Old 2003-12-12, 12:37   #2
Prime Monster
 
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I think that would be quite difficult. Prime95 is designed to use all the unused CPU cycles in your machine without taking any cycles from other programs.

The program is already running at lowest priority, so that cannot be changed.

PM
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Old 2003-12-12, 12:45   #3
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If you do LL-testing (afaik only then - correct me if i am wrong) you can reduce the heat your CPU generates using the Throttle-option decribed in UNDOC.txt
Quote:
If you are running on a laptop or in a hot room and you want to slow the
program down to reduce heat, then you can add this line to prime.ini:
Throttle=n
where n is the number of milliseconds to sleep after each iteration.
But why do you want to do this? Is it a heat problem or do you want to make sure, that other programms are not slowed down during prime95 operation?

If the latter is the case, there is no need to do so with almost all programs because (like PM said) prime95 runs on idle priority.
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Old 2003-12-12, 12:46   #4
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There really is no need but if you must it is fairly simple just read the UNDOC.TXT file and look for throttling.

Last fiddled with by Complex33 on 2003-12-12 at 12:47
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Old 2003-12-12, 16:45   #5
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Unless your CPU is halted it is always running at 100 % it is just a matter of what program(s) are getting the CPU time, either it is wasted in an endless idle loop in the kernel or some program such as prime95 makes use of them.

The previous posts about using the throttle parameter in prime.ini will approximate the lower percentage you mentioned.
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Old 2003-12-12, 17:13   #6
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Quote:
Originally posted by dsouza123
Unless your CPU is halted it is always running at 100 % it is just a matter of what program(s) are getting the CPU time, either it is wasted in an endless idle loop in the kernel or some program such as prime95 makes use of them.

The previous posts about using the throttle parameter in prime.ini will approximate the lower percentage you mentioned.
Not true. When the CPU is idle it eats less power and generates less heat. In a hot room, even if you have decent air cooling, you can get 40-45°C inside the case, wich is quite a lot for the HDD. This is why I asked for the Throttle feature (yep it was me :)). It is better to run Prime95 at 60% than not run it at all.
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Old 2003-12-12, 17:41   #7
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Exactly what is NOT TRUE ?

1. If the CPU is not halted it is running. TRUE
2. If no other program is requesting the CPU time then the Kernel ( OS ) will get the CPU cycles using it's idle loop ( a waste of CPU cycles ). TRUE
3. The throttle parameter will APPROXIMATE the percentages stated. TRUE

I never mentioned power or heat.
Neither did the original post.
If prime95 is sleeping (as a result of implementing the throttle feature) then some other program is using the CPU time.
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Old 2003-12-12, 18:20   #8
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In W98 or earlier, you are right...

In W2K, WXP & Linux the processor will go into a state of "sleep" if there is no work to do...

It makes for a significant decrease in temps... My old laptop runs blistering hot in W98 at idle, but running WXP is it very cool running...
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Old 2003-12-12, 20:02   #9
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hey flava, i remember you asking for the throttling feature. let me ask you what you use as a delay time for this. i may implement this in some laptops
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Old 2003-12-12, 20:36   #10
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Quote:
Originally posted by dsouza123
Exactly what is NOT TRUE ?

1. If the CPU is not halted it is running. TRUE
2. If no other program is requesting the CPU time then the Kernel ( OS ) will get the CPU cycles using it's idle loop ( a waste of CPU cycles ). TRUE
3. The throttle parameter will APPROXIMATE the percentages stated. TRUE

I never mentioned power or heat.
Neither did the original post.
If prime95 is sleeping (as a result of implementing the throttle feature) then some other program is using the CPU time.
It is not true that the CPU runs at 100% when Idle. Unless you consider that doing nop's is "running". For me a CPU works at 100% when there are no nop's, every cycle being used for add's, mul's and such. We should NOT mislead those who ask questions about CPU usage by suggesting that an idle CPU and a fully charged CPU are the same. If there was no difference, why the extra power consumption and heat?
A good computer in a normal environment will handle this extra heat without problems. A computer with poor cooling or a computer kept in a warm environment WILL BE PRONE to hard disk failures and/or fried CPU if it runs what I call 100% all the time. Remeber that not all CPU's have a built-in throttle feature.
I hope I answered your question.
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Old 2003-12-12, 20:44   #11
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Quote:
Originally posted by delta_t
hey flava, i remember you asking for the throttling feature. let me ask you what you use as a delay time for this. i may implement this in some laptops
Right now I don't use it because my computer is in a relatively cool room. In the summer I used a 20 or 30ms throttle (CPU at about 80%). The temperature inside the house was about 30-32°C, the CPU at 100% was at 59°C and the MB at 46°C. With the throttle at 20ms, the CPU was at 54°C and the MB at 41-42°C.
A MB at 46°C spells "disk failure". I know what I'm talking about, my old disk died this way.

Last fiddled with by flava on 2003-12-12 at 20:44
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