What is DDR5?
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Short answer
DDR5 is fifth-generation double data rate synchronous DRAM (DDR5 SDRAM) — the main-memory technology standardised by JEDEC as JESD79-5. Micron describes DDR5 RAM as fifth-generation double data rate random-access memory based on DRAM cells (capacitor + transistor), transferring data on both edges of the clock (Micron, What is DDR5 RAM?). JEDEC published the JESD79-5 DDR5 SDRAM standard to raise bandwidth and improve power efficiency versus prior DDR generations (JEDEC press release, 14 Jul 2020).
This page explains what DDR5 is. Choosing between generations: DDR4 vs DDR5. How memory differs from a drive: RAM vs SSD.
What the name means
| Term | Meaning (Micron) |
|---|---|
| RAM | Broad name for a computer’s working memory |
| DRAM | Dynamic RAM — the common main-memory cell technology |
| SDRAM | Synchronous DRAM — timed to the system clock |
| DDR | Double data rate — transfers on rising and falling clock edges |
| DDR5 | Fifth generation of DDR SDRAM |
What JEDEC standardised
When JEDEC announced JESD79-5, it highlighted architecture and power changes aimed at client and server systems (JEDEC):
- Burst length doubled to BL16 and bank count to 32 (from 16) for channel efficiency at higher speeds.
- Each DDR5 DIMM carries two 40-bit independent sub-channels.
- Launch data rate expected at 4.8 Gbps, about 50% above DDR4’s end-of-life 3.2 Gbps.
- VDD reduced from 1.2 V (DDR4) to 1.1 V.
- On-die ECC and related scaling features.
- Module-level voltage regulation on the DIMM (pay-as-you-go scalability / tighter voltage tolerance).
- Decision Feedback Equalization (DFE) for higher I/O speeds.
The living standard document is JEDEC JESD79-5 (DDR5 SDRAM); JEDEC’s catalogue lists current revisions for download by members/subscribers (JESD79-5 page).
Micron’s DDR5 vs DDR4 feature snapshot
Micron publishes a side-by-side feature table. Selected rows (Micron DDR5 SDRAM):
| Feature | DDR4 | DDR5 |
|---|---|---|
| Data rates | 600–3200 MT/s | 4800–8800 MT/s |
| VDD / VDDQ / VPP | 1.2 / 1.2 / 2.5 V | 1.1 / 1.1 / 1.8 V |
| Device densities | 2–16 Gb | 16, 24, 32 Gb |
| Prefetch | 8n | 16n |
| Burst length | BL8 (and BC4) | BL16 (and BC8 OTF) |
| On-die ECC | None | 128b+8b SEC, error check and scrub |
| Bank groups | 4 BG × 4 banks (x4/x8) | 8 BG × 4 banks (16–64 Gb x4/x8) |
Micron also states DDR5 can deliver up to about 2× memory bandwidth versus DDR4 at 3200 MT/s, and that DDR5 modules are not physically or electrically compatible with DDR4 boards (Micron).
What DDR5 is not
- Not a form factor. DDR5 comes as UDIMM, SODIMM, RDIMM and other module types; the generation is the DRAM standard, not the stick shape.
- Not interchangeable with DDR4. Wrong notch / signalling — Micron: DDR5 fits only DDR5 motherboards (Micron FAQ).
- Not the same as “ECC RAM” for the whole channel. JEDEC/Micron on-die ECC corrects errors inside the DRAM die; module-level ECC for the path to the CPU is a separate product/platform choice (see DDR4 vs DDR5).
- Not storage. Capacity and speed of system memory are separate from SSD capacity — RAM vs SSD.
FAQ
What does DDR5 stand for? Double Data Rate 5 (DDR5) SDRAM — fifth-generation DDR synchronous DRAM (Micron; JEDEC).
Is DDR5 measured in MHz or MT/s? Micron uses MT/s for transfer rate; MHz for the clock. Because transfers occur on both edges, the familiar “DDR” doubling applies (Micron FAQ).
Should I buy DDR5 or DDR4? That depends on the CPU/motherboard — covered in DDR4 vs DDR5, not here.