FUD Zilla reports Intel isn't planning to replace DDR3 until at least the first half of 2014:
It looks like there won’t be any new desktop or mobile memory standards that can get us excited at least until 1H of 2014.
The current plan for Intel is to stick with DDR3 and the low power variant, simply called DDR3L with voltages up to 1.5V. The current plan is that Haswell, a CPU that comes in 1H of 2013, supports DDR3 and DDR3L at 1.5V 1600 with dual channel memory interface. Broadwell 14nm might change this but only in 1H 2014 and beyond.