Win XP detects my S3 Savage4 video board correctly and installs drivers for it (signed, new and flashy, but without any of the advanced controls that I used to have in Win 98). Problems:
1. from time to time, apparently random, the system halts and Win reboots saying that there was a problem w/ the video driver (looks like some sort of infinite loop)
2. using some games (*not* fancy 3D stuff, actually those work fairly  good) and switching to some video modes lead to a garbled colorful screen (neat looking too) that again is followed by forced reboot

S3 site says that WinXP should comne packed with the best drivers around and there is no driver d/l area... . Win update site says there are no updates available for me  :(

Is there smth I can do? Is there a workraound? I really am not willing to teach myself XP's DDK and write my own driver :P

Only thing I can think of is that you may need to move some of the cards around in your system.  There may be some IRQ sharing going on that would cause this.  I had a similar issue when I went from 98 to 2k.  Everything worked fine in 98 but in 2k I had to move my tv tuner card to a different slot to get it to work without locking up.