Newer CPUs don't necessarily use more power, even though they get more done. I added an X1950 to my aging system to make it passable for Source games, but between that card, the P4 Northwood, four hard drives, a TV tuner, etc. I wouldn't dream of using a PSU advertised less than 500W. I blew out a 500W Antec within the past year with this setup (damn you VRAD!).