Update: 2.4.20 with -preempt works also on my hardware.
junkieclown -- have you tried 3123? There's a remote possibility that that might help... What I see as different between our setups (your KT333, at least) is:
Manufacturer of the card itself (mine's an MSI)
Manufacturer of the motherboard (Biostar POS)
Distro (LFS hybrid, but it did work a while back on Mandrake 8.2, IIRC that was 3123 or 2960 though)