I just checked the LKML and poked around the SIS site as you have an SIS735 chipset packaged for you into a motherboard by ECS.
The SIS735 has had some wonky support through the past year since it was introduced... but it should be fine now. About the only thing I found that could still be causing problems is if this machine is running on a rather cheap power supply and one of the higher XPs... maybe. Its probably something else, are you 100% on the drives?
Also, to take care of sound and maybe help out on video, you might want to try this site directly from SIS:
http://www.sis.com/support/driver/linux.htm
Cheers,
Finegan