Why won't DX10 drivers run under XP? Again--it's because the driver model Vista requires is incompatible with XP.
Quit drinking the Kool-Aid, WaltC. They could easily port DX10, or some compatible variant, over to XP. They made giant leaps between DX7 and DX9 on XP. DX9 to DX10 is no different.
The fact is, 100% of my games run worse in Vista, even the DX10 ones. And this is coming from someone who has both installed on his system. Thank God I got Vista for free- I'd shoot myself in the foot if I paid for it. Aesthetically, I love it- but for games, it's horrible.
This brings back up the old question- why won't developers start to support Linux? PC Gamers were hardcore enough to embrace DOS, and the most recent releases of Ubuntu have been extremely user friendly, fast, and still free. I guess we run into the classic "chicken and the egg" scenario here.