The A7N8X Deluxe has a 3Com NIC onboard as well as the nVidia one. I've used both as heavily as one can use a 100Mbit NIC, and they both seem to be ...well, they both seem to be normal 100Mbit NICs, which is to say they could stand to be faster!
That's one of the features of the A7N8X
-E Deluxe, it has the onboard nVidia 100Mbit NIC (not PCI-based, but native to the MCP-T southbridge), but the second NIC is a gigabit-Ethernet NIC that's based off the PCI bus.
Regarding the PCI bus, I had a KT333-based board which proved to have nasty PCI performance. The PCI bus seemed to be topping out at 70MB/second even with as much PCI stuff disabled as possible (that motherboard had some extraneous stuff hung off the PCI bus, like USB 2.0). By contrast, even the original nForce was busting the door down with 120MB/sec sustained throughput, and nForce2 is the same. Bye-bye KT333...
With
two Ultra160 cards riding that bus, I'm not gonna put up with half-baked PCI performance.