Serial ATA performance
The Serial ATA disk controller is one of the most important components of a modern core logic chipset, so we threw each platform a selection of I/O-intensive storage tests using a Western Digital Raptor X.

IOMeter
We'll begin our storage tests with IOMeter, which subjects our systems to increasing multi-user loads. Testing was restricted to IOMeter's workstation and database test patterns, since those are more appropriate for desktop systems than the file or web server test patterns. Keep in mind that because we couldn't get the SB600 south bridge running in AHCI mode, Native Command Queuing isn't enabled, putting the 790FX at somewhat of a disadvantage.

That disadvantage becomes clear rather quickly when the 790FX's transaction rate fails to take off as the number of concurrent I/O requests increases. Performance does scale as the load increase, but not nearly as quickly as the 590 SLI. It is worth noting, however, that the 790FX offers higher transaction rates with extremely low and extremely high load levels; it's just slower in the meat of the curve.

IOMeter response times track with transaction rates, with the AMD chipset proving slightly quicker at the extremes and the nForce delivering better performance in the middle.

The nForce 590 SLI exhibits higher CPU utilization than the 790FX in IOMeter, but only by about half a percent.