Okay so I decided to get a XFX 8600 GTS from Tigerdirect since I wanted a budget upgrade to play some games (maybe hour everyday or maybe couple hrs a week). When I received it with my Powerup 450watt psu and OCZ PC2 6400 2gb sli ready ram I was super happy. However when I installed everything I got a MACHINE_CHECK_ERROR on my computer when I booted up or sometimes it just froze. So I was like really annoyed so first I switched rams out and yet same problem. Then I decided to switch my 8600 gts to my 8600 gt and wow the problem disappeared. Now my problem is I dont want to run my 8600 gt when I have 8600 gts but it just won't work for some reason. I installed the 175 WHQL drivers from Nvidia but I still have the same problem. I currently have a Pentium E2180 2GHZ cpu overclocked to 3ghz and a 650i Ultra T1 motherboard. Does anybody have a single clue to whats wrong?