Installed a new AMD 2400 athlon mobo this weekend and knoppix 3.3(the latest works.
Conclusion: If you want to use knoppix avoid systems which are SIS based. Also PCchips based systems. If you have a very very good PC hardware knowhow (and likewise linux) you might be able to tweak the SIS/PCchips system to work with knoppix but judging from the response to this thread, very few people use it for linux.