I've been trying to run Houdini in Win2k, but for some reason the hardware acceleration doesn't work at all with Geforce. I have to switch the acceleration to the 2nd lowest setting (software mode) otherwise the 3D viewport is really slow or has some strange visual anomalities.
I've tried this with different drivers from nvidia and asus, ranging from 5.16 to detonator 3 and even with 2 different cards (asus 6600 and 7100). There are some minor differences how it works with different drivers, but basically none do work for real.
(Tried also with matrox g200 just for the record, and g200 didn't have any problems at all...)