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CPU not running at full speed while stress testing.

  • CPUs
Last response: in CPUs
March 5, 2008 9:14:37 PM

Hi lads!

I just got my PC to work! It's my first build, so i'm ever so happy!

My CPU is a E8400.
Anyhow, i downloaded some software, CPU-Z, Prime95 and CoreTemp.

And while running Prime95 i noticed that my CPU-Z recorded only around:
Core Speed 2671,5MHZ
multiplier set at x 8.0
rated FSB at 1333.6
Bus speed at 334.0mhz.
Volt at 1.192

Okay. I am aware of speedstep but since i'm stress testing it i assume that this will tell the CPU to work at full throttle! So what is the problem?

I havn't updated my Motherboard yet since i got it out of the box, could this have any influence?

I also have another quick question(s) :) :
- how long should i be running prime95 (and which test would be suitable? (blend and so on)
- My temp wont raise above 49 while stress testing but my CPU heatsink is litteraly chillingly cold, i have to use midgets to touch it. Is this normal? (that the heat wont dispatch to the whole heatsink?). It's cold all over.

Cheers. And thanks! :) 

More about : cpu running full speed stress testing

March 5, 2008 9:58:55 PM

I'm not too familiar with the E8400 but the first thing I see is the multiplier. Normally with Intel Core 2 CPUs its 9, and drops to 6 under speedstep, so check your bios to see if it's set to 9 normally.

Also, as far as what test you want to use depends on what you want to test. Typically errors show up in an hour or so but whenever I do an overclocking build I do 8-24+ hours (I ran my current build for 72 hours, overkill but I went away for the weekend unexpectedly)

A CPU below 50 with a cold heatsink means that everything's working properly and that heat's getting the hell out quickly :) 
a b à CPUs
March 5, 2008 10:42:21 PM

If you're running Vista, check your power management settings. Look at the processor settings, there will be a minimum and maximum setting (in %). If you are using a power saving plan the maximum will not be at 100% and therefore will not let the CPU run at full speed. If it is <100% change it and see if that solves your problem.
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March 5, 2008 11:09:52 PM

Ah. Thank you both.

It was the multiplier! It's at 9x now, i don't know why it was set at 8x.
Also, i changed the power settings from balanced to High performance. . dunno if it changed anything but thank you for the notice.

March 6, 2008 9:28:58 AM

Well. . i'm in school now, and at home i'm running Prime95 at fourth hour.

I was wondering, does it stress test both cores in the dual core processor? or only one?

Anyhow, i choosed the setting blend in prime95 and i'm looking forward for the results. . I havn't seen the temp above 49. Even after i changed my CPU to 3ghz.
March 6, 2008 10:04:30 AM

I'm only running one "instance" i think (sorry does this mean, like, one program of prime95? English is not my native language :) ).

I just downloaded the newest version and ran the program in a blend test.

by the way, your link is not working (or maybe it's mozilla?).
March 6, 2008 10:49:32 AM

uh well. . when i came back my computer had rebooted :S . . hmm