So far there is only G.Skill offering commercially available memory kits, which can be driven a 4GHz clock speeds. These days at IDF Corsair is showing memory modules which also manage to break the 4GHz barrier, which lets us hope that 4GHz kits from Corsair are going to be available soon.
Corsair is demonstrating their 4GHz memory on an Intel Skylake based system, which is using an Intel Core i7-6700K CPU and Z170 chipset. To be a bit more precise, the test system has been equipped with Corsair Vengeance LPX DDR4 memory sticks. Unfortunately there aren't too many additional details being communicated by Corsair, which leaves us guessing.
Currently there are quite a few overclockers busy breaking memory frequency world records, while 4.8GHz+ have already been achieved using extreme cooling methods and single channel configurations. This fact makes it appear likely that Corsair is running a dual-channel setup at 4GHz with stock cooling. But as we already mentioned, the vendor remains silent when it comes to details.
Apart from the details system specs there is also no information on a launch date. Nevertheless it could be possible that Corsairs 4GHz kit are going to be launched soon.
Source:
KitGuru