Corsair announced it managed to overclocked a single DDR3 memory module to 2462MHz:
Verified and validated by CPU-Z, Corsair Labs achieved an astounding speed of 2462MHz at CL=9 with a single-rank 1GB module. This new world record eclipses all previous CPU-Z validated memory benchmarks. This record was set using Corsair’s award winning DOMINATOR DDR3 memory module paired with an Asus P5E3 Premium motherboard based on the Intel X48 chipset. This is now the highest achieved DDR3 frequency of all time.