DDR4 is not compatible with any earlier type of random-access memory (RAM) due to different signaling voltage and physical interface, besides other factors.

[1][8][failed verification] Unlike previous generations of DDR memory, prefetch has not been increased above the 8n used in DDR3;[9]: 16  the basic burst size is eight 64-bit words, and higher bandwidths are achieved by sending more read/write commands per second.

Unlike DDR3, DDR4 does not have a low voltage variant; it consistently operates at 1.2 V. Additionally, DDR4 improves on DDR3 with a longer burst length of 16 and supports larger memory capacities, enhancing both performance and system flexibility.

[11][12] In April 2013, a news writer at International Data Group (IDG) – an American technology research business originally part of IDC – produced an analysis of their perceptions related to DDR4 SDRAM.

[41] A switch in consumer sentiment toward desktop computing and release of processors having DDR4 support by Intel and AMD could therefore potentially lead to "aggressive" growth.

DDR4 was introduced with a minimum transfer rate of 2133 MT/s, influenced by DDR3's nearing limit at similar speeds, and is expected to reach up to 4266 MT/s.

Early DDR4 samples, such as those from Samsung in January 2011, showed a CAS latency of 13 clock cycles, comparable to the DDR2 to DDR3 transition.

[9]: 16 Protocol changes include:[9]: 20 Increased memory density is anticipated, possibly using TSV ("through-silicon via") or other 3D stacking processes.

[31][44] In 2008, the book Wafer Level 3-D ICs Process Technology highlighted concerns about the increasing die area consumption due to non-scaling analog elements like charge pumps, voltage regulators, and additional circuitry.

These components, including CRC error-detection, on-die termination, burst hardware, programmable pipelines, low impedance, and a greater need for sense amplifiers (driven by reduced bits per bitline due to lower voltage), have significantly increased bandwidth but at the cost of occupying more die area.

[1][47] In addition to bandwidth and capacity variants, DDR4 modules can optionally implement: Although it still operates in fundamentally the same way, DDR4 makes one major change to the command formats used by previous SDRAM generations.

The purpose of UniDIMMs is to help in the market transition from DDR3 to DDR4, where pricing and availability may make it undesirable to switch the RAM type.

In 2011, JEDEC introduced the Wide I/O 2 standard, which features stacked memory dies placed directly on top of the CPU within the same package.

This configuration provides higher bandwidth and improved power efficiency compared to DDR4 SDRAM, thanks to its wide interface and short signal lengths.

Wide I/O 2 is designed for high-performance, compact devices, often integrated into processors or system on a chip (SoC) packages.