At CES 2014 after micron, now ADATA has also shown their DDr4 memory with a capacity of 8Gb and 16Gb @2133Mhz, timing CL15 and standard voltage is 1.2v which is less than DDr3 Memory.

But still those Ram are not for the consumer. Actually, those are R-DIMM which is used on the server, but we know that from this Fall Intel Next Generation platform Haswell-E will support DDr4 and for mainstream platform we will have to wait for next year for Intel to introduce the mainstream Skylake OR Braswell Platform.