Bizarre hardware problem causing restarts under load

[HunacFunac]

I've tried several games including Battlefield 4, Metro 2033, Kerbal Space Program, and also refreshing my "Windows Expreience" rating. All of these cause a grinding beeping sound to come out of my computer after 15 seconds to a minute. The monitor will shut off and my computer will automatically restart itself. Curiously, some newer games are unaffected, like Starcraft 2 and Counter-Strike GO.

I recently upgraded my video card from a GTX 460 to a GTX 650 ti Boost. Afterwards, my computer began restarting under load. I thought the card was faulty, so I RMAed it. The new card suffered the exact same problem. After research online, the universal consensus for this problem was a power supply issue. So I bought a new power supply. I swapped out my old PC Power and Cooling Silencer 620W for a new XFX 550W (the one with Seasonic internals). The same problem persisted. I also reformatted my computer (Windows 7 64-bit) to rule out any software issues. Now I'm at a loss. It's not the video card, power supply, or any software issue. My processor is an AMD X3 445, about two years old. Could this be a symptom of a dying processor?

I'm at a loss of where to go from here and would appreciate any insight. Thanks a bunch.

 

[danny2000]

Well, the computer could be overheating when you are running at full load. Have you checked your temps? Your motherboard probably came with software that you can install to view the motherboard and cpu temps.

Have you tested your hard drive?
Reseated the ram? although I doubt that that would be your problem here.

 

[HunacFunac]

Ok, I ran CPUID's HWMonitor to check my temps. My processor was sitting at 38-39C, and I refreshed Windows Experience to test it. Some fan in my computer got really loud, and my computer restarted. I launched HWMonitor again first thing, and my CPU temp was at 48C and falling fairly quickly, leading me to believe it got even hotter at the moment of the restart. That sounds like it could be the problem. How would I go about troubleshooting that? Thanks again

 

[danny2000]

Can you tell if it is the cpu fan or not?

Also, see if you can test the temps when playing one of your games that has the problem with restarts.

 

[danny2000]

oh, btw, did you uninstall, reboot, and reinstall the nvidia drivers when you switched to the new video card? you should.