I've got a Inwin full tower that is about 6 years old, it has a 235watt ps that is original, it has run 24x7 for 6 years with various mb's, right now it has a 1gig thunderbird, with 256megs, 32meg video card Asus A7v, 6 fans, 2 7200rpm hd's, 12x dvd, 12x cdrw, ide zip, lan card, modem, sound board, tv tuner card, it just works. Power supply rating means nothing, they stamp whatever they want on them, I've had 300watt supplies that didn't last 24hrs.