do you really care? i've got a nvidia 4000 series gfx card so i've had to use the dodgy patched executable and shaders and hte game crashes regularly, but i'm still enjoying it.
Its kinda shit that bethesda haven't bothered to try and make it compatible with graphics cards out there and so loads of peeps are having problems, but even if you whack down the resolution (mines at 800x600) and turn off loads of the special shit like pretty trees, grass and water its still a frickin sweet game.
If you're dead set on getting everything as good as it can be, then there might be info on the main oblivion forums...
http://www.elderscrolls.com/forums/i...p?showforum=23
personally i'd just give up, the game is good enough without the sweetass graphics.