For those with an onboard or pci-e version having similar issues, http://realtek.com.tw
downloads -> communications -> network -> gigabit -> pci express
click on software, then move down to
'LINUX driver for kernel 2.6.x and 2.4.x (Support x86 and x64)' (highest version)
Remember to blacklist the native r8168 in favor of the r8169.ko from realtek.
Tested under 64bit 1337, ~70MB/s, zero issues.
Shows up as 'RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 03 and 06)'
You'll need kernel headers/source installed to build the r8169.ko module.