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's 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 nForce4 boards were tested with the NVIDIA Firewall and Jumbo Frames disabled.

The KA1 MVP continues to disappoint in our Ethernet performance tests, where the throughput of its PCI Express Marvell 88E8053 Gigabit controller trails the competition's. Note that the same Marvell chip offers much higher throughput on the RDX200 and A8N32-SLI. CPU utilization is lower on the ECS board, but that's likely an artifact of the board's lower throughput.

As expected, the KA1 MVP's 10/100 Fast Ethernet controller doesn't come close to matching the competition's throughput. The chip's high CPU utilization is even more disappointing and certainly unjustified given its slow transfer rate.