SATA performance
I used HDTach for these benchmarks. They're largely intended to find a problem with throughput, CPU utilization, or both. I used HDTach's 8MB zone size setting for all tests. The hard drive was a Seagate Barracuda V with SATA interface.

The nForce4 Ultra's performance mirrors that of the competition, and we don't see any major problems here.

ATA performance
These tests are HDTach again, but with a Seagate Barracuda V with ATA/100 interface.

ATA performance is much the same story. For most intents and purposes, the three Athlon 64 chipsets perform identically, and the Intel 925X is quite similar, too.