I've installed the oem.tgz with realtek drivers r8168.o, on Asus M48785t-m Mother board with ESXi 4.1, Nic is working fine but i have errors in the log:
ct 8 05:27:40 vmkernel: 0:01:12:02.137 cpu1:4123)<3>RTNL: assertion failed at vmkdrivers/src26/drivers/net/r8168/r8168_n.c (1771)

Also when i Alt F11 on the host another error is present:

cpuo:4798) ELF 3028: Kernel Module r8168 was loaded, but with no signature attached.

I've looked every where for answers as to why and what these errors means, with no real good solution. The nic works fine from my basic tests so far but i havent loaded it up. Any info would be much appreciated..

Thanks

The second error just means that the driver hasn't been digitally signed by VMware. No worries there.

I'm not sure about the 1st error. For performance I would look at iperf - viewtopic.php?f=14&t=1604&hilit=iperf.