I suggested 600w because I do not know his system specs, he didn't list anything on it. AMD recommends 400+, but the guy could have multiple PCI cards, a demanding CPU, multiple drives, etc. I also recommended 600+ for future proofing, you do not just want to reach the bare minimum requirements for your system, thats never a good idea considering you can short out components by under powering them. Anyways, a 600-650w psu can be picked up on ebay fairly cheap, as low as $40. Only here to help! Have a nice day.