Here's our current test system.

Our test OS was Windows Vista Ultimate SP1 x86 with 175.14 Forceware drivers, 18.11 nForce drivers, and ATI Catalyst 8.4. All the latest software revisions were used in our testing.

Let's start off with some game benchmarks.

Here in game benchmarks we don't see a huge difference in scores. The 590 chipset is limited though somewhat by the 1GHz Hypertransport bus as opposed to the 2GHz of the others.

PCMark gives a good base of general PC performance and the Crosshair does quite well. In 3DMark 2006SE the  790FX barely comes out on top but that the difference is minute enough to be a variable.

HDTach's test again shows the 790FX and 780a closer than the 590SLI but the 780a comes out on top.