Kingston hasn't started shipping any DDR4 memory kits yet but the company has just made a major change to the specifications of its HyperX DDR4 modules. Legit Reviews notes that while pre-production kits that were send to a number of review sites ran at 1.5V, the retail kits will be programmed to run up to 1.35V depending on what kit you purchase. Kingston says internal testing showed 1.5V isn't necessary with the latest DDR4 ICs and PCB combination.
Legit Reviews recently had an X99 platform failure and one of the areas of concern was the high voltages that the Kingston HyperX Predator 16GB (4x4GB) 3000MHz memory kit was running. We are happy to hear that Kingston has lowered the voltages as it wasn’t really needed and will reduce temperatures and hopefully improve the reliability and lifespan of the memory kits. After speaking with many Intel engineers that worked on Haswell-E we do not think out platform failure had to do with the 1.5 Volts running on this particular DDR4 memory kit as the Haswell-E processors memory controller supports both DDR3 and DDR4 memory. DDR3 memory comes standard now at 1.5V, but many kits are still on the market at 1.65V. Since Intel designed the memory controller to work with DDR3 and many Intel Xeon processors are using the same core architecture with DDR3 memory kits just fine, we can safely assume the higher than normal DRAM voltage isn’t to blame. Intel also recently came out and let us know that 1.2-1.5V is the acceptable DDR4 Voltage range for Intel X.M.P. 2.0 memory kits.