Intresting article ... wonder how true it is
DX10 is do-able on Windows XP
The original reason was that DX10 required graphics memory to be virtualisable, a laudable goal. You can see hints of it here and here among other places. This was a good thing, perhaps a really good thing, and Microsoft was clamping down on requirements with the usual subtlety of a convicted monopolist.
This would not work with XP, and that was fine and dandy. It was an honest technical reason why you could not backport DX10 to XP without a major rip and replace operation. Microsoft wasn't going to bend on this one at all.
Then something odd happened. Nvidia had about as much success implementing this required feature as it did with it Me II drivers, that is to say, none. It couldn't do it, but it was required for DX10. What's an arm twisting Vole to do? Backpedal obviously.
So, MS threw NV a life preserver and made GPU memory virtualisation completely optional. ATI, which had implemented a dandy memory virtualisation scheme got screwed, or at least got what everyone who partners with MS got. Oh wait, I said that.
In any case, in doing this, MS removed the only impediment to backporting DX10 to XP, it is now, and has been for quite a while, completely possible. MS is screwing its customers to force an upgrade and you are a pawn in their revenue generation scheme.
Sadly, I will admit that I did upgrade. I went from XP to Ubuntu and bought a Wii. Life could not be better now, gaming is fun again, and spyware is a distant memory.
DX10 is do-able on Windows XP