The reason i got the 500Watt is because i had a 300 running the Athlon 2400+, dual 80GB Hard drives, DVDRW, Audigy 2 NX (external), usb printer, usb card reader, usb webcam, the radeon 9800 and it kinda died on me hahahaha so i opted for the 500 just to be safe, i think its a mercury, not amazing but it was in the case when i bought it