An anonymous overclocker cracked a staggering DRAM speed (for dual-channel), using Intel Core i7-3770K processor (engineering sample) and ASUS Maximus V Gene motherboard, at DDR3-3256 MHz. The overclocker started off at DDR3-3153 (~1576 MHz actual) on boot, and carefully notched it up to DDR3-3256 (1628 MHz actual) in Windows. 16 GB of memory of an unknown make, was used.
What makes the feat impressive is that such DRAM clock speeds are difficult for dual-channel/multiple-module setups, and reserved only for single-module feats. Ahead of the launch of the 3rd Generation Core "Ivy Bridge" platform, every motherboard vendor is covertly showing off similar overclocking feats.
A video recording of the feat follows.
Source: OCWorkbench