Whenever I play a graphics intensive game (Assassins Creed 3, Sleeping Dogs, Skyrim) I can get about 5-10 minutes of gameplay before my system completely shuts down. No error is shown beforehand - my monitors just lose connection, the fans start to spin at max RPM and then the computer just shuts down. I've monitored the temperature's while under load and the max I would get is 75 degrees. While idle my system runs at about 30-40 degrees. I've tried two different PSUs, one being a 430W Corsair, and the other being a 650W Coolermaster. So the PSU doesn't seem to be the issue.
The cx430 won't power that system under full load.
That coolermaster PSU is crap and probably makes only like 400w so that's no good either.
I'm guessing this is your problem.
Thanks for the response. The only thing that is weird though is that one I first built the system awhile back (December) I would be able to play Crysis 2, Far Cry 3, Hitman Absolution, etc at max settings for hours. This was using the Corsair 430. It's only recently that the computer would crash under load with the 430 and the 650.
* Power supplies get hot, and this heat is, of course, wasted energy. The specification requires an efficiency of 70%, and recommends one of 80%. That's still a fair amount of loss – your 550W PSU is drawing 650W at the wall.
There are higher efficiencies available, and there's a whole green movement to promote them. However, try not to get too carried away with it and spend a fortune on a 95% efficient supply. Electricity is still relatively cheap, and you probably won't see any large return for your outlay. I recommend models on the '80 Plus' or any model that's Energy Star +4.0-rated.
* Another factor you should consider is the loading. Like most machinery, a power supply has sweet spots where it's most efficient. You need to avoid the extremes, and that why I always said add 20% wattage for what your PC needs. You wouldn't drive from City to Other at an average speed of 30mph. Nor would you make the same trip at 150mph (even if you could get away with it). Sure, it's possible to drive at such speeds, but you'll burn through fuel much quicker than if you cruised at the optimum speed.
It's the same with PSUs: you should aim for a load of between 50% and 80% – anything more or less will introduce waste.