I just recently decided to attempt to OC my XFX 7750 to 900mhz using CCC to see if I noticed any increase in fps while playing any of my games. After OC my screen immediately went black for about 6 seconds and then returned noting that my display drivers had temporarily failed. Oddly programs were still responsive and all temps were good 35c range. I then proceeded to boot WoW, black screen, failed drivers, than Far Cry 3, same thing happened, GW2 same thing happened. I went back to CCC, turned off my GPU and memory OC's and everything ran fine great again, high framerates... Any ideas? I've looked around and although there are some people having similar issues the problems they are having are not due to overclocking.
AMD Phenom II BE 965 (OC'd to 3.9ghz)
Gigabyte 780g 78LMT-S2P Mobo
8GB Kingston Hyper X Blu Ram ddr3 (2x4gb)
XFX 7750 800mhz ddr5
ThermalTake 600w TR2 psu