I have two custom build computers:

Computer A - Shuts down due to CPU overheat (Mobo = MSI 870A Fuzion Power Edition [MS-7660])
Computer B - Works perfectly fine (Mobo = Asus M4A78LT-M-LE)

I have stress tested two different CPU's with their own fans (multiple times) in each computer using a program called Prime95 whilst monitoring their temperatures with a program called Open Hardware Monitor. Here are the CPU specs and test results:

CPU A - AMD Phenom II X4 955 (3.2 GHz Quad Core)
CPU B - AMD Athlon II X2 270 (3.4 GHz Dual Core)

Computer A + CPU A = Shutdown @ 121 degrees C
Computer A + CPU B = Shutdown @ 108 degrees C
Computer B + CPU A = Stable @ 99 degrees C
Computer B + CPU B = Stable @ 99 degrees C

The results indicate to me that the shutdowns are due to CPU overheating, however this is not caused by the CPU's or their fans as they both run fine in computer B. Could anyone please suggest why the CPU's are running fine in computer B but not computer A?

(If any further details are needed, please let me know and I'll try to provide them.)

  • Have you looked inside the BIOS of both computers ? Usually there is a possiblitiy to adjust these settings there... – Martin Verjans Nov 24 '16 at 13:45
  • @MartinVerjans I enabled AMD Cool n Quiet on Computer A but this didn't help unfortunately, I can't see any other options that might be able to help or limit the CPU temperature. – user2397418 Nov 24 '16 at 14:30

First off let me start off with neither of those chips should be anywhere NEAR that temperature. Even Overclocked by 1ghz and Over voltaged by an INSANE 0.1175v my Phenom II 940 BE was only at 49c running prime 95 and Othrus simultaenously... and I considered that unsafe

It may be the program you are using is not properly reading the temps, but due to the shutdown(s) I think it may be correct

IIRC, my Phenom max safe range per the spec was 60c. It sounds like you do not have adequate cooling on either of these machines, or the cooling wasn't properly installed. Anytime that you have a computer shutting down due to temperature... you need to take a step back and evaluate cooling. I am surprised that neither if these chips have caught on fire yet. Even more surprised they are still running.

Check your cooling. Make sure that the heat sinks are properly installed, and that the thermal paste is properly applied. Make sure your case and PSU fans are working and properly venting heat out of the case / bringing in fresh cool air.

You may need something other than the stock cooling. The above phenom when overclocked was using a Zalman CNPS9700 and Arctic Silver thermal paste. The case was an antec 900. After backing down the voltage and the overclock a little from above (+1v and +700MHz) this chip never ran hotter than 42c for 3 years.

  • Thanks for the info, I will likely replace the thermal paste for both CPU's anyway, however I'd still like to understand why they are both working in one PC but not the other. – user2397418 Nov 24 '16 at 22:30
  • I would say it has something to do with the motherboard features. They B may not be pushing the CPU as hard, which is why the temps are 10-20 lower. The safety cut off is probably 100c which means that computer B is on the edge of a safety shutoff as well. – Kevin Howe Nov 25 '16 at 1:38

This issue is now solved. Installed a new motherboard (ASUS Sabertooth 990FX R2.0), all other hardware is the same, and the CPU is no longer overheating with the Prime95 stress test but instead runs stable at a maximum of 89 degrees C. The old motherboard was the cause of the issue - whether it was faulty or not, I don't know.

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