personally Dot i wouldnt go any less than a 750 watt PSU cause if you do and you want to add a nice video card and multiple hard drives and sound cards and shit 500 wont do the job very well...not saying it wont work but youll end up burning it out before its time dude especially if you run a PCI express vid card most have a minimum power requirement and 500 isnt the magic number for some research or talk to a local PC store that builds custom machines{NOT BEST BUY EITHER!} real computer builders. anyways just dont want to see ya spend money on a PSU and then have to get another in a few months when ya decide to upgrade your video card or hard drives and shit. I personally have 3 custom machines 1 with a 750 watt psu and 2 with 1000 watt psu's. LaterZ.