DDR5 vs DDR4 server memory: what actually changed and when should you upgrade?
DDR5 is in new servers. DDR4 still runs most of what is already deployed. This is what actually changed between the two, which platforms support DDR5, and when the upgrade makes sense.
What actually changed
DDR5 is not just a faster DDR4. The architecture is genuinely different in ways that matter for server workloads.
The headline number is bandwidth. DDR5 starts at 4800 MT/s where DDR4 topped out at 3200 MT/s. But two less-publicised changes matter more in practice. First, the voltage regulator moved from the motherboard onto the DIMM itself. That means more precise power delivery per module, less electrical noise, and better stability across configurations. Second, DDR5 includes on-die ECC as standard. Error correction now happens at the chip level before data reaches the memory controller. For databases and virtualised workloads, that extra layer is not a nice-to-have.
Per-DIMM capacity also jumped. DDR5 supports up to 128GB per module versus 64GB for DDR4. For memory-dense workloads, that matters.
The numbers side by side
| Spec | DDR4 | DDR5 |
|---|---|---|
| Base speed | 2133 MT/s | 4800 MT/s |
| Max speed | 3200 MT/s | 6400 MT/s+ |
| Max per DIMM | 64GB | 128GB |
| Voltage | 1.2V | 1.1V |
| On-die ECC | No | Yes |
| Bandwidth | ~50 GB/s | ~100 GB/s |
| Backwards compatible with DDR4 | n/a | No |
DDR5 and DDR4 use different physical slots. You cannot install DDR5 in a DDR4 server. The connector is different and the module will not fit. Do not try.
Which servers support DDR5
DDR5 needs a DDR5-capable memory controller. The controller is part of the processor and motherboard, so this is fixed per server generation.
HPE ProLiant
Gen11 supports DDR5. Gen10 and Gen10 Plus are DDR4 only. If you have a DL360, DL380 or ML350 and it is Gen11, you are good. Earlier than that, you are not.
Dell PowerEdge
16th Gen (R760, R860, R960) supports DDR5 on Sapphire Rapids and Emerald Rapids processors. 15th Gen is DDR4.
Lenovo ThinkSystem
V3 generation supports DDR5. SR630 V3, SR650 V3, SR850 V3 all work. V2 and earlier are DDR4 only.
RDIMM or LRDIMM?
Buy RDIMM. That is the answer for the vast majority of servers and workloads.
LRDIMM goes to 128GB per module and reduces the load on the memory controller, which allows higher total capacity in slots-constrained configs. But it costs significantly more and has slightly higher latency. You would only consider it if you need more than 64GB per slot and your server explicitly supports it. If you are not hitting that ceiling, RDIMM is the right call.
When to upgrade
If your server supports DDR5, use DDR5 when adding or replacing memory. There is no good reason to buy DDR4 for a DDR5-capable platform.
If you are on an earlier generation, you cannot upgrade to DDR5 without replacing the server. The memory controller is baked into the hardware. Plan for DDR5 on your next refresh cycle.
What it costs now
DDR5 used to carry a meaningful premium over DDR4. That gap has closed significantly. As of early 2025, DDR5-5600 32GB RDIMMs are priced competitively with equivalent DDR4 configurations. For new Gen11 or equivalent deployments, the economics work.
Email us at sales@verilicense.co.uk with your server model and what capacity you need. We will come back to you the same day.
Common questions
Can I mix DDR4 and DDR5 in the same server?
No. Different physical slots, not interchangeable, cannot coexist in the same system.
What if I mix different DDR5 speeds?
All modules run at the speed of the slowest one. It works but you lose the benefit of the faster modules. Match them if you can.
Does ECC work the same way on DDR5?
DDR5 has two layers. On-die ECC catches errors at the chip level first. Your server’s memory controller then applies system-level ECC on top. It is a more robust setup than DDR4, which only had the system-level layer.
The bottom line: if your server supports DDR5, buy DDR5. If it does not, plan for it on your next hardware refresh.