I'm not sure which one fixed the problem, but a combination of upgrading the BIOS and switching to the new kernel update that was pushed out (2.6.15-25) resolved the problem for me.
-- PCI issues affecting 3ware Inc 7xxx/8xxx-series and RTL-8169 Gigabit Ethernet https://launchpad.net/bugs/48061 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs