Performance System Memory: DDR3 Memory Read & Write
Performance System Memory: Memory Read Test
So for memory we had some good stuff to work with, Intel has a couple of certified partners for memory to get some sweet XMP profiles going.
Now with the regular memory at 1600 MHz versus AIDA memory tests we see good performance hovering at the 24-25K marker. With XMP enabled at 2133 MHz read/write perf jumps to ~33K. The effect if memory performance however is trivial in many ways.
Faster memory is relative though, your overall PC experience will not be incredibly faster, yet a few percent with memory intensive applications like say transcoding, or a CPU limited game. Every bit helps though you need to relate it into the money you invest versus the satisfaction you will get out of it.