Games Freezing(still)

In my last post we determined here that my PSU was inadaquate. While this was true I have replaced it with a 750watt namebrand. Unfortunately When i play games that required any stress on my system it locks up and i have to reboot. I have resorted to playing Diablo II as of late. I ran memtest86 for 2 hrs and no errors were logged. And i ran Prime95 overnight for 7 hours. The system is still doing fine this morning. I know the system is not overheating either, all temps run in the green and games lockup before they would even get a chance to get hot(usually in Menu). Any suggestions?

A8N-SLI
Athlon X2 4600+
1 Gb PC 3200
GeForce 6800GT (x2) in SLI
Creative X-Fi Fatal1ty
750 W Enermax PSU