BSOD Radeon 6850

I posted earlier that I was getting the bsod everytime I tried to play a fullscreen game. Concluded that it is because I have a cx430w psu. I just ordered a new antec 750w, but I want to make sure thats the only issue. I don't wanna get this psu in 3-4 days and have it happen again lol.
It doesn't matter if I run Dirt3 or League of Legends, i get like 3-10 minutes gametime and then black screen followed by sound crashing, which results in a painful hard restart.

Mobo: ASRock Extreme z68
Cpu: i3-2120
Gpu: Sapphire Radeon 6850 HD
PSU: cx430 my antec gamer series 750w is on its way

Connections on cables and slots are all good and secure...
What else should I look into on this matter?
What other info should I post here?