I've got a 3000+ athlon xp with 1GB of ram, an ASUS A7V8X mobo, a 6600GT, 2 Rom drives and 1 HD drive, 3 case fans and a soundblaster live 5.1. As of now i have a Thermaltake Purepower 420 Watts PSU which runs at 18A on the 12V. Would my psu hanldle if i were to put in a 6800GT or a 6800 ultra? Thanks!