XP does come with drivers for the Savage2000, but by default there is pretty poor OpenGL support. The main problem was that the drivers for Windows 9x/ME were far more mature than the drivers for Windows 2000 were when support for the card was dropped. The XP driver is merely a follow on from the last Windows 2000 drivers and even then they lack some features.
There has been some
new (non-tweaked) drivers released for the Savage2000 but these are not much better in terms of performance and only fix a few errors.
Really you should stick with Windows 98/ME or get a new card for XP.