HD Tach
We used HD Tach 3.01's 8MB zone test to measure basic SATA throughput and latency.

The nForce's burst speed is a little quicker than that of the 790FX, but the big difference between the two comes in HD Tach's write speed test. This test tends to run much faster on platforms that support Native Command Queuing, which would explain why the 780a has such a big lead.

A 0.1-millisecond difference in random access time doesn't amount to much.

HD Tach's CPU utilization results are well within the app's +/- 2% margin of error for this test.

USB performance
Our USB transfer speed tests were conducted with a USB 2.0/Firewire external hard drive enclosure connected to a 7200RPM Seagate Barracuda 7200.7 hard drive. We tested with HD Tach 3.01's 8MB zone setting.

The 790FX's aging SB600 south bridge has long-standing USB performance issues that comparison with 780a makes all too clear. Not only does the nForce achieve higher burst, read, and write speeds, but it does so with lower CPU utilization, as well.