Basically it works for some people on low Wattage power supplies, and doesn't for others. It depends on the manufacturer of the PS (a reputable manufacturer vs a no-name brand) and especially on your current setup for your computer. Depending on if you have a lot of hard drives, ROM drives, PCI cards, etc (more stuff in your case that draws power) you may or may not be able to get away with a low-watt PS. I'd say 300 should be fine as long as you don't have too much stuff in there, otherwise you might wanna play it safe and get a quality 350+ W PS.