My vendor had to install a beta BIOS in order to get ethernet working on Ubuntu 6.06.
Sounds like a problem with the Kernel Ubuntu uses, Ill have to check it sometime as I certainly didnt do this and got a K8WE right when they were released. My ethernet is working fine with the forcedeth driver, though I havent tested it at gigabit speeds yet.
For the record I only have a single chip in it now, looking to upgrade to twin dual cores, but works great for me with an NVidia card and RME HDSP 96/32, <3mS latency with no problems, I could probably push it farther but dont really have a need to.
Seablade