Well thats becuase Halo for the PC has a tweaked DX9 engine. It has a bunch more features.
But I have to agree with Tibs. My friend has an XBOX (I would never buy its just too taboo.
) and we were playing this chronicles of riddick demo. The graphics on their are sweet.
Well then Doom III came out. I was unsurprised with the graphic hype. But since I am running it on a geforce4 I guess I should hold my comments until I get my 6800 back.
But yeah the Xbox is dedicated technology and such so it can run faster.