Well actually the dx9 final hasn't been released yet. I read somewhere that it may support PS 3.0 & VS 3.0 also
(But that is unsure) The Radeon 9700 supports PS 2.0 & VS 2.0 and the upcoming GeForceFx supports PS 2.0+ & VS 2.0+. So it has more advanced shaders than dx9 provides. The Radeon 9700/pro, GeforcefX & Matrox's card are NOT 100% dx9.0 compliant. None of them support dicplacement mapping 100% which is part of dx9. Installing dx9 on the dx8.1 (or lower) will not boost it's performance but adds SOME dx9 effects which can be done by EMULATING. Installing dx9 on dx9 card will make the next-gen card to use dx9 effects & it gives the card makers the opportunity to optimize the drivers so the card will run at maximum performance.
__________________
Compare link[2K1]1956