Yeah, it came with the case, What wattage should I have to support my system?
amps on the (+)12v line is usually more important for a GPU. what amps does yours have?
+ manufacturer of case??
Depends on the power supply. A 450 watt Corsair probably would. A 450 watt Antec might. A 450 watt generic probably wouldn't.
The current rating of the 12 volt output is critical.
EDIT: Turns out it's only a 400W, I was told it was 450W. Here's a pic, cos I don't know much about power supplies.
looks like a FSP psu (from what i gathered from the code.) They have an excellent reputation and the 12v amps don't look to bad either. They're used in the Dell gaming boxes if i remember correctly
FSP is a decent brand. Only 400W though, with 27A on the combined +12V rails...I'm not sure that's quite enough, not for overclocking those parts. Making arbitrary assumptions about your system, I got 363W using a NON-overclocked 4850. Stock, it needs 9A, so overclocking probably adds 1A-2A to that, or 12W-24W. It looks like technically that PSU could handle it, but you'd be running on the edge, which is asking for trouble. I don't think I'd do it.