Isolating New Build Error

Mileryen

Honorable
Nov 17, 2012
2
0
10,510
Hey all,

Threw together a new desktop for the wife last week, hardware is:
i5 3570K (3.4 GHz)
WD 500GB Blue HDD (5400 rpm)
MSI Z77A-G45 Mobo
Gigabytle Geforce GTX 650 Video Card
Themaltake 600w PSU

Running Windows 8 Home Prem. It's stable when coasting on the desktop, browsers, etc. but will crash within 5-60mins of doing anything more intensive such as gaming, editing, etc. Crash is just a power off immediately followed by a reboot. No BSOD even with automatic restart turned off in control panel. Windows logs show nothing useful... just a kernal event where power was cut unexpectedly with no additional info. What I've tried so far:

-Switched out video card with the video card in my other stable desktop, same issue
-Pulled PSU and switched in PSU from my other stable desktop (650w compared to 600w), same issue
-Updated all drivers to both the newest release as well as the newest beta release, same issue
-Reformatted and clean installed Windows, same issue
-Prime 95 blended torture test for 36 hours, no errors or crashes
-Ensured all fans are spinning properly (CPU, Video Card, case, etc.)
-Monitored core temp of CPU while gaming induced crash, couldn't get CPU heat over 44C in any core regardless of how many games/windows/processes open at once which shouldn't be in the ballpark of overheating

I'm at a complete loss :( My gut feeling is that it is an overheating issue, but I can't get anything to substantiate that hunch. I'm still well within my return policy on all parts at a local store that matches NewEgg for prices (!) but I don't really want to just start returning everything through them until I can find the faulty part by process or elimination.

Thanks in advance for the long read and the advice!