There's no real memory performance improvement when simply overclocking using the multiplier on the 7750 Black Edition - here's a bit more read and copy performance but without being able to increase the northbridge clock the write performance remains the same. The overclocked Intel E5200 performance increases greatly as we jacked up the FSB from 800 to 1,333MHz - the write performance in particular makes better use of the same DDR2-800MHz at 4-4-4-12-2T.
Intel's latency also drops by nearly 23 percent, but the new Athlon doesn't see much of a latency improvement at all.