The adoption of DDR4 was delayed as DDR3 DRAM prices stabilized last year. Higher margins prompted memory makers like SK Hynix and Samsung to continue making DDR3 instead of moving over production capacity to DDR4, which would have been more expensive to make. Memory makers also delayed DDR4 after demand for PCs fell. In addition, Intel and Advanced Micro Devices delayed DDR4 adoption after the emergence of ultrabooks, which use low-power DDR3 memory.
Companies like Samsung, Micron and Kingston demonstrated DDR4 memory after the DRAM specification was finalized in September 2012. Samsung has already started manufacturing the memory for commercial use, and Micron's Crucial business unit is demonstrating DDR4 memory at the International CES show being held this week in Las Vegas.
The DDR4 bus clock speed will top out at 3200MHz, an improvement from 2400MHz for DDR3, and 1.2 volts will be supplied for DDR4 compared to 1.5 volts for DDR3. DDR4 reliability is considered higher because of more debugging and diagnostic tools to prevent data errors.
DDR4 is expected to be the final iteration of DDR DRAM. There is a move to others forms of non-volatile memory that can retain data. Alternative forms of memory under development include phase-change memory, RRAM (resistive RAM) and MRAM (magnetoresistive RAM). Memory makers like Micron are also stacking chips to deliver faster throughput, and Nvidia plans to stack memory chips in its upcoming graphics chip code-named Volta.