PC crashing issues

I'm having an issues with my CPU crashing when I start up battlefield 3 and play for a few minutes. I just moved to a new house and this problem started I thought it may be a software or driver issues but when i crash it look like i hit the shutdown button. No blue screen or any errors come up. I thought this may be a power issue but i have changed my power supply and also bought an apc ups 1300va 785 watts backup battery power pack. Ive been searching the web and some people have said this may be a heat issue My GPU's run at 48 to 54 C at all time while gaming. All fans are working and I reseated all my CPU components and reapplied thermal compound.

My reg
AMD Phenom9tm) IIx4 965 processor 3.41GHz
Ram 8 GB corsair
64bit operating system
Nvidia 460 video card
asus sabertooth 990fx motherboard
corsair tx 650 w power supply

 

Have you run memtest?

Is it only Battlefield 3? If yes, uninstall, wipe all traces of the game from your hard drive, then reinstall and see if that helped.

 

I have and it looks to be ok. I uninstalled bf3 and installed another game and it did the same thing. Turned my CPU off like I hit the shutdown bottom.

 

That could actually be your power supply. How old is it?

Since you're a gamer, it seems a fairly safe assumption your GPU is a GTX 460. If that's the case, then you have a video card that requires a minimum PSU of 450W. Yours was 650W on day one, but they lose a bit of muscle every year they are in use... eventually they are shadows of their former selves. Kind of like professional athletes, who don't age well either. If your PSU is a few years old, it might not be able to power your GPU for heavy work anymore.

Easy way to test: Borrow a more powerful PSU and see if that helps.