Memory performance
Memory subsystem performance doesn't always track with real-world applications, but it's a good place to start.

Thanks to AMD's on-die memory controllers, we don't see much difference in memory performance here. The 790FX has the lead in Sandra's memory bandwidth test, but only a fraction of a nanosecond separates the two platforms when we probe CPU-Z memory latency.

Memory controllers don't always handle four DIMMs gracefully, so we popped an additional two memory modules into each system for another round of tests.

With an additional two DIMMs onboard, the 590 SLI manages to close the gap in Sandra. Latency scores remain close.

The following latency graphs are a little indulgent, so I won't be offended if you skip them. They show access latencies across multiple block and step sizes, painting a full picture of memory controller performance with each chipset. Yellow represents L1 cache, light orange is L2, and dark orange is main memory.

Same on-die memory controller, same overall latency performance. Move along.