Question Computer keeps losing power/restarting while performing light tasks

gamer4717

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Jul 24, 2015
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My computer is randomly restarting without warning while performing light tasks. It is as if the PC loses all of its power then turns back on. I've checked my temps and CPU utilization as well as ran memtest86 and the Intel processor diagnostic tool and all of that didn't lead to those respective parts being diagnosed as faulty. I did, however, have problems with running prime95. When I would run the small-FFT test, almost immediately after starting it, the PC would shut down identically to how it's been doing. I'm thinking its either the motherboard or the power supply, but I'm not too sure what the culprit might be.

Specs:

CPU: i7 4790k
MOBO: GA-Z97X-UD5H-BK
RAM: 2x4gb 1866mhz corsair vengeance.
PSU: Corsair CX600M
 
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My first thought based on your description was power supply and it is fairly easy to test if you have access to another power supply or a retailer with a generous return policy.

Could it be the motherboard ... of course.

I assume it never restarted while running memtest. If you ran that diagnostic for a time longer than it normally takes to crash, that might point to software corruption (ie .. .it crashes under Windows, but not if you don't boot Windows). Software corruption does normally lead to a freeze/blue screen, but it is possible that it would cause a restart.

Other possibilities are less likely and kinda nutty ... the kind of things that it would be really hard to test for.
 
Finally found the culprit for real this time. Turns out it was the CPU. After swapping it out with an i5 4690 I had from a trash picked system, it could actually run the small FFT torture test on prime95. I am kinda bumbed out about it but oh well.
 
Another update to this problem and it has just got weirder. I swapped the CPUs around in the two machines I have. I put the faulty CPU in the other machine and after running some tests, it isn't crashing.
 
I put the 4790k back into its respective machine and I still experienced the same issue with it crashing. So I had been running the F8 Bios on this board, so I decided to downgrade back to F7 and it fixed the problem with it crashing in prime95 (for right now at least).