What is DDR4 RAM? - Explained

DDR4 DIMM SDRAM

Image of a DDR4 DIMM SDRAM.

DDR4 RAM is the superseded family of DDR3 SDRAM which is from double data rate technology. DDR4 SDRAM introduced in to the global markets in 2014 which means 7 years after DDR3 SDRAM release which was in 2007.


What is DDR4 RAM?

DDR4 SDRAM does have higher module density and lower voltage requirements and higher data rate transfer speeds. Comparing with the DDR3 DIMM RAMs DDR4 DIMM RAMs allows up to 64GiB, which was 16GiB in DDR3 SDRAMs.

In DDR4, the prefetch has not been increased beyond 8n which was used in DDR3. Though the DDR4 SDRAM allows 8 words at the burst size and higher bandwidths were achieved by sending out more and more read and write requests with a single second. To achieve multiple requests, DDR4 does have DRAM banks which can be clustered into two or four selectable groups of DRAM banks. This allows the RAM to transfer data into multiple locations in the same RAM but with different address locations.

Notch difference of DDR3 DIMM SDRAM and DDR4 DIMM SDRAM.

The DDr4 SDRAM does require 1.2 volts and 1.4 volts with a range of frequency between 800MHz and 2133MHZ. DDR4 does not compatible with backward usability, which means the DDR4 SDRAM cannot be used in DDR3 SDRAM sockets due to the architecture differences and the notch difference in the both RAMs. And DDR3 SDRAMs also cannot be used in the DDR4 SDRAM due to difference of the notch and the difference in the architecture of the components.