the X-box doesn't need to run an operating system and also, the X-box is more optimized for gaming than any PC could ever be simply by the nature of the way PCs and consoles are made and designed for. Also, a PIII @ 1200mhz is more powerfull the a P4 @1200mhz so P4>P3 isn't always true, if you went on an oerclocking frenzy the PII is actually the best choice(I have heard stories of a man overclocking a PII to 10000mhz with liquid nitrogen cooling and a huge ass power supply.) EDIT: I would like to note that most current PCs drastically over power the PS2, X-box, and the Gamecube.