I was not happy with the throughput using the onboard NIC so I installed the 3com Gigabit NIC which supports jumbo frames. NIC is not recognized by OS as standard so you have to get the driver from Asustek:
http://dlsvr01.asus.com/pub/ASUS/lan/3com/3c940/046_Solaris.zip
Just follow the instructions provided and your NIC will be recognized and fully functional.
