my 2 cents
while I dont have the exact same hardware/setup as you mine does work...now..
msi master2 MB with 2 opteron 242
chaintech FX5600 256MB
suse 8.2 amd64
2.6.0 test11 kernel /* no apic, no agpgart */
I had constant lockups under the 2.4.xx kernels, I tried everything I could think of. It would work fine for a little while then hard lock. seems to be agp related IMHO. 2.6.0 kernel solved MANY things for me SATA support,sound etc.etc. and it is more responsive too. dont forget to upgrade modutils for the new kernel. Oh and you HAVE to use the nvidia openGL libraries. or else it wont start or you get like 100FPS in glxgears so completely remove the mesa libs.
and as with all xf86 stuff, start with just the bare bare minimum, get that to work and go from there.