Ethernet performance
We evaluated Ethernet performance using the NTttcp tool from Microsoft's Windows DDK. The docs say this program "provides the customer with a multi-threaded, asynchronous performance benchmark for measuring achievable data transfer rate."

We used the following command line options on the server machine:

ntttcps -m 4,0,192.168.1.25 -a

..and the same basic thing on each of our test systems acting as clients:

ntttcpr -m 4,0,192.168.1.25 -a

Our server was a Windows XP Pro system based on Asus' P5WD2 Premium motherboard with a Pentium 4 3.4GHz Extreme Edition (800MHz front-side bus, Hyper-Threading enabled) and PCI Express-attached Gigabit Ethernet. A crossover CAT6 cable was used to connect the server to each system.

The boards were tested with jumbo frames disabled.

Can you guess which Gigabit Ethernet options are constrained by PCI bus bandwidth? I thought so. At least Asus bolsters the P5Ks' networking capabilities with PCIe GigE controllers that can manage over 900Mbps. The IP35 Pro isn't so lucky; it's stuck with two PCI-based GigE chips that put it a good 200Mbps off the leaders in Ethernet throughput.

To Abit's credit, the IP35 Pro does manage low CPU utilization during the throughput test, but it's pushing fewer bits, so it should. Among the boards with proper throughput, the P35 Platinum and GA-P35-DQ6 offer the lowest CPU utilization.