DDR5 RDIMM
DDR5 RDIMMs are the standard memory for current two-socket servers built on 4th and 5th Gen Intel Xeon Scalable and AMD EPYC 9004/9005. Each module carries its own power management IC and two independent 32-bit sub-channels, which is why DDR5 kits behave differently from DDR4 when you mix them.
Population rules are stricter than before. Eight channels per socket (Intel) or twelve (AMD) means the fastest configuration fills one DIMM per channel with identical parts. Dropping in a single extra module in the wrong slot can cut bandwidth in half or stop the server posting.
At a glance
| Speeds | 4800, 5600, 6400 MT/s (platform dependent) |
|---|---|
| Capacities | 16, 32, 64, 96, 128, 256 GB per module |
| Voltage | 1.1 V, on-module PMIC |
| Platforms | PowerEdge R660/R760/R6625/R7625, ThinkSystem SR630 V3/SR650 V3, Supermicro X13/H13 |
| Ranks | 1R, 2R, 4R (3DS for 128 GB and up) |
What RackLedge does
- Sizing and DIMM-per-channel planning for new servers
- Matched-kit upgrades using vendor-qualified part numbers
- BIOS and iDRAC/XCC firmware baselines before a memory change
- Memory error triage: correctable vs uncorrectable, ADDDC, page retirement
- Performance validation after install (memtest, STREAM, application benchmarks)
How we work
A memory engagement starts with evidence, not a parts list. We pull utilization from your monitoring or hypervisor, confirm memory is the real constraint, and only then choose modules that keep every channel populated at full speed.
Firmware comes first. BIOS and BMC updates fix memory training bugs and unlock newer module types, so we baseline them before opening the chassis. Installation is scheduled in a maintenance window and validated with a memory test and an application check before the server goes back into rotation.
Parts are new or tested refurbished with a warranty, matched to the vendor's qualified list or an equivalent specification, and we keep a record of exactly what went where so the next upgrade starts from documentation rather than guesswork.
Related services
More on server memory
Frequently asked questions
Can I mix DDR5 module sizes?
Within one channel it is best not to. Across channels the server may run, but it will drop to the slowest common speed and you lose interleaving. Buy matched kits.
Do I need vendor-branded memory?
No, but you need modules on the vendor's qualified list or an equivalent spec. Third-party parts that match SPD data work well and cost less; we can source and validate them.
Need a hand with this?
Tell us what you are running and what is slowing you down. You get a straight assessment and a plan, with no obligation. Support desk is staffed 24/7.