Crashing after switching graphics card

[HotdogMan]

I switched to a GTX 660 from a GT 630 and noow most of the games crash after a few minutes of playing
There are no signs of overheating and the fans don't get loud, most of the games arent even that gpu intensive
I have fresh installed drivers and still crashes
but when I switch back to the 630 everything works fine
The psu is 500w Apevia Switching power supply WIN-500XSPX
If there is anymore info needed just ask and I can provide

 

[TJ Hooker]

Does it crash to desktop, or does the whole computer shutdown?

 

[HotdogMan]

It different for games, sometimes it freezes until I shut the computer off and sometimes it freezes then after a wile unfreezes for a minute before doing it again