According to Nvidia they have had to write the drivers for Vista from scratch, so its safe to assume it takes time and does not seem to be easy either. Now this has lead to some negative colleteral issues aswell. Because Nvidia is putting all its effort on Vista & 8800 cards, basicly older gen cards and XP support has been left to cold. Not a pretty situation
The only problem I've had with my 8800GTX with XP Pro isnt really with the OS, just with an issue with shadows in Half-Life 2. Not a big deal, and thats it(so far). This is one of the many reasons I'm not getting Vista just yet.
how can they invent a new tech. (dx10) and not back it up with the drivers also. will they finally give us a driver only when the 8900 is out? (to hell with the 8800s?)