be aware the more overpowered the PSU, the less efficient it is used. I measured my system at work (quad core, 4 gb ram, 1 hdd, 1 dvd, gf 9600 GT passive) and the whole system sucks only about 120 Watts (minus screen) at full load (prime95 + gpu raycasting) of course the "non passive" latest & fat versions of the graphics…