sounds like increasing the voltage to 1.48 was BAD. The CPU got too hot and shutdown the system. 600watts sounds like enough for a minor OC of 3 to 3.2ghz, so I doubt its your PSU. When your OCing, are you bumping up the multiplier or FSB. If your increasing your FSB, it might be that your entire system (RAM, NorthBridge, SouthBridge, PCI controllers) are OC'd too much and can't handle it. I know my integrated GPU fails even with just a 12.5% OC! Try increasing your multiplier instead. It won't speed your entire system up, but it'll get your CPU to 3.2GHz without affecting the rest of your system!