A Dell PowerEdge memory upgrade comes down to a handful of facts: the generation, the module type, the channel count and what is already installed. Get those right and the server starts first time. This guide walks through each one, from the model number to the iDRAC inventory, with the memory every generation takes from the 12th generation through the 17th.
The short answer
- The model number tells you the generation. An R740 is 14th generation and takes DDR4. An R760 is 16th generation and takes DDR5. DDR4 and DDR5 do not fit each other's slots.
- Most PowerEdge servers take ECC registered memory (RDIMM). DDR4 generations can also take LRDIMM for the highest capacities. DDR5 generations (16G and 17G) take RDIMM only.
- Entry servers take unbuffered ECC memory (UDIMM) only. The R250, R350, T150 and T350 will not start with registered modules.
- PowerEdge does not require Dell branded memory. iDRAC reports the maker and part number of any module that meets the specification, and the server runs at full speed with no lock.
NEMIX RAM supplies memory for PowerEdge matched to the model. Start from our Dell PowerEdge memory page, or browse PowerEdge rack servers and PowerEdge tower servers.
How to read a PowerEdge model number
The model number tells you the memory generation before you open a manual. Take the R7625. R is the form factor, 7 is the performance class, 6 is the generation (16G), 2 is the socket count, and the last digit is the processor vendor: 0 for Intel and 5 for AMD. Three-digit models such as the R760, R650 and T550 drop the socket digit.
| Prefix | Form factor | Examples |
|---|---|---|
| R | Rack | R760, R660, R7625, R6615, R750, R740xd |
| T | Tower | T560, T550, T440, T350, T150, T630 |
| C | Cloud and multi-node sleds | C6620, C6615, C6525, C6420 |
| XE | GPU and AI systems | XE9680, XE8640, XE7745, XE9640 |
| MX | Modular (MX7000 chassis sleds) | MX760c, MX750c, MX740c |
| FX | Flex modular (FX2 chassis sleds) | FC640, FC630, FC430 |
| XR | Rugged and edge | XR8620t, XR7620, XR5610, XR4520c |
| HS | Hyperscale | HS5610, HS5620 |
PowerEdge memory by generation
| Generation | Example models | Processors | Memory | Channels per socket |
|---|---|---|---|---|
| 17G | R770, R670, R7715, R6715, XE9780 | Intel Xeon 6, AMD EPYC 9005 | DDR5-6400 ECC RDIMM. Select Intel configurations accept MRDIMM-8800. | 8 (Intel) or 12 (AMD) |
| 16G | R760, R660, R7625, R6625, R7615, R6615, T560, C6620, XE9680, XR7620, MX760c | 4th and 5th Gen Xeon Scalable, EPYC 9004 | DDR5-4800 ECC RDIMM. DDR5-5600 on 5th Gen Xeon and EPYC 9004 refresh. No LRDIMM. | 8 (Intel) or 12 (AMD) |
| 15G | R750, R650, R7525, R6525, R7515, R6515, R750xa, T550, C6525, MX750c | 3rd Gen Xeon Scalable, EPYC 7003 and 7002 | DDR4-3200 ECC RDIMM or LRDIMM. 3DS RDIMM at 128GB and 256GB on select models. | 8 |
| 14G | R740, R640, R740xd, R7425, R7415, R6415, T640, T440, C6420, MX740c, FC640 | 1st and 2nd Gen Xeon Scalable, EPYC 7001 and 7002 | DDR4-2666 or DDR4-2933 ECC RDIMM or LRDIMM. 2933 requires a 2nd Gen Xeon, and 1st Gen runs 2666. | 6 (Intel) or 8 (AMD) |
| 13G | R730, R730xd, R630, R530, R430, T630, T430, R830, R930, M630, C6320, C4130, FC630 | Xeon E5-2600 v3 and v4, E5-4600 v4, E7 v3 and v4 | DDR4-2133 or DDR4-2400 ECC RDIMM or LRDIMM. 2400 requires v4 processors. | 4 |
| 12G | R720, R620, R720xd, T620, R520 | Xeon E5-2600 and v2 | DDR3-1333, 1600 or 1866 ECC RDIMM or LRDIMM. Low-voltage 1.35V modules on most configurations. | 4 |
| Entry single-socket | T160, T360, R260, R360 | Xeon E-2400 | DDR5-4400 or DDR5-4800 ECC UDIMM | 2 channels, 4 slots |
| Entry single-socket | T150, T350, R250, R350 | Xeon E-2300 | DDR4-3200 ECC UDIMM | 2 channels, 4 slots |
| Entry single-socket | T40, T140, R240, R340 | Xeon E-2200, Pentium | DDR4-2666 ECC UDIMM | 2 channels, 4 slots |
| Entry single-socket | T130, T330, R230, R330 | Xeon E3-1200 v5 and v6 | DDR4-2400 ECC UDIMM | 2 channels, 4 slots |
These generation lists are representative. The Dell part number on the installed module, or the 370 code on your order, is the authority for your exact server. Send us the Service Tag if you are unsure.
RDIMM, LRDIMM or UDIMM: which does your PowerEdge need?
RDIMM is the standard ECC registered module and the right choice for most PowerEdge servers. LRDIMM is load-reduced memory that exists to reach the capacity ceiling on DDR4 platforms, up to 2TB to 3TB per socket. UDIMM is unbuffered ECC memory used only in entry servers. RDIMM and LRDIMM cannot be mixed in any PowerEdge. If the system already holds one type, that decides it. DDR5 PowerEdge servers do not take LRDIMM, so high capacities there use 128GB and 256GB RDIMMs instead. For the registered types in detail, see the RDIMM, MRDIMM and MCRDIMM guide, and for the unbuffered ECC types see our ECC vs non-ECC RAM guide.
Popular PowerEdge models
- R640 and R740 (14th generation). DDR4-2666 or 2933 ECC RDIMM or LRDIMM, 6 channels per Intel socket. See the R640 and R740 memory.
- R650 and R750 (15th generation). DDR4-3200 ECC RDIMM or LRDIMM, 8 channels per socket. See the R650 and R750 memory.
- R660 and R760 (16th generation). DDR5-4800 ECC RDIMM, with DDR5-5600 on 5th Gen Xeon. See the R660 and R760 memory.
- R7625 (16th generation AMD). DDR5 ECC RDIMM on 12 channels per EPYC socket. See the R7625 memory.
- R250 and R350 (entry rack). DDR4-3200 ECC UDIMM, 2 channels, 4 slots. See the R250 and R350 memory.
- T350, T550 and T560 (tower). The T350 is an entry DDR4 ECC UDIMM tower, the T550 is 15th generation and the T560 is 16th generation DDR5. See the T350, T550 and T560 memory.
For wider Dell coverage across laptops, desktops and workstations, see the Dell memory buyer's guide.
Population rules that decide whether it starts
- One module type per system. RDIMM and LRDIMM cannot be mixed in any PowerEdge, and entry servers take UDIMM only. If the system holds RDIMM, add RDIMM.
- Fill channels before doubling up. A two-socket 16G server has 16 or 24 channels, and a two-socket 15G has 16. Dell's population table, white slots A1 through A8 first and then the black B slots, keeps every channel active. A single 64GB module in an 8-channel socket runs at one-eighth of the available bandwidth.
- Balance both sockets. The BIOS expects symmetric population across processors. Loading one socket and leaving the other empty leaves that processor with no local memory and a performance warning at start-up.
- Match capacity, speed and rank within a socket. The BIOS drops to the slowest module, and mixed ranks or capacities in one channel can force a lower speed or block Mirror and Fault Resilient modes. Identical modules are the safe configuration.
- Two modules per channel costs speed. DDR4-3200 typically runs at 2933 with two per channel on 15G, and DDR5-4800 drops to 4400 with two per channel on 16G. Decide whether the workload needs capacity or bandwidth before choosing 8 x 32GB over 4 x 64GB.
- The processor sets the ceiling. A 14G board accepts 2933 modules, but a Xeon Gold 5118 runs them at 2400. Check the processor's rated memory speed before paying for the faster grade.
- Operating modes need symmetric population. Optimizer is the default and accepts any valid layout. Mirror halves usable capacity and needs identical modules in paired channels. Fault Resilient and Single Rank Spare have their own layout tables in Dell's service manual.
Find what is installed without downtime
- iDRAC web interface. Go to System, Inventory, Hardware Inventory, Memory. Every slot is listed with capacity, speed, rank, module maker and the Dell part code.
- racadm from a shell. Run racadm hwinventory or racadm get System.Memory for the same inventory as text, which suits a fleet script.
- Dell Support. Enter the Service Tag and choose View original configuration. The memory lines carry the 370 codes and capacities the system shipped with.
- OpenManage Enterprise. It exports memory inventory across the whole estate in one report, which is the right starting point for a multi-server quote.
How much memory to add
Typical 16G and 15G two-socket configurations ship at 128GB to 256GB. The workloads that justify the next step are virtualization hosts, which run out of memory long before processor, so 512GB to 1TB lets a host carry twice the virtual machines. In-memory databases and SAP HANA are sized to the dataset, commonly 1TB to 2TB. Analytics and AI inference nodes, the XE and R760xa class, scale system memory with GPU memory. VDI is the memory per desktop multiplied by seat count, plus headroom.
Will non-Dell memory work in a PowerEdge?
Yes. PowerEdge has no vendor lock on memory. A module that meets the Dell-qualified part on every attribute the memory controller checks (generation, capacity, ECC, buffering, speed, rank, voltage and pin count) runs at full speed, and iDRAC reports the maker and part number with no warning. Mixing NEMIX RAM with Dell branded modules of the same part number in one system is supported. Memory is a customer-replaceable unit on every PowerEdge, so the support contract stands, although Dell may decline to troubleshoot an issue it attributes to third-party modules. That is what our lifetime warranty and support cover.
How to upgrade the memory in a PowerEdge
- Identify the model and read the generation from the model number, or send us the Service Tag.
- Read the installed memory in iDRAC: type, capacity, speed and rank.
- Choose the module of the same type and generation, matched in capacity and rank to what is installed, or replace a small mismatched set with a matched kit.
- Size the kit to the channel count, and fill both sockets symmetrically.
- Install and check. Power down, follow the slot order in the service manual, then confirm the full capacity in iDRAC or the BIOS on first boot.
Send us the iDRAC inventory or the Service Tags and the target capacity, and we return a matched set. For fleet and refresh planning, see our data center memory refresh guide and data center server memory page. Browse DDR4 RDIMM, DDR4 LRDIMM, DDR5 RDIMM, DDR4 ECC UDIMM and DDR5 ECC UDIMM.
Related guide: Server will not start after a PowerEdge memory upgrade? Causes and fixes by vendor
Frequently asked questions
What memory does a Dell PowerEdge R740 take?
The R740 is a 14th generation server that takes DDR4-2666 or DDR4-2933 ECC RDIMM or LRDIMM, with 6 channels per Intel socket. 2933 requires a 2nd Gen Xeon Scalable processor, and a 1st Gen runs at 2666. The R640 takes the same memory.
What memory does a PowerEdge R760 take?
The R760 is a 16th generation server that takes DDR5-4800 ECC RDIMM, and DDR5-5600 on 5th Gen Xeon, with 8 channels per socket. It does not take LRDIMM.
What memory does a PowerEdge R350 take?
The R350 is an entry single-socket server that takes DDR4-3200 ECC UDIMM, with 2 channels and 4 slots. It takes unbuffered modules only, and registered modules will not start.
Can I mix RDIMM and LRDIMM in a PowerEdge?
No. RDIMM and LRDIMM cannot be mixed in any PowerEdge. If the system is populated with RDIMM, add RDIMM.
Does a DDR5 PowerEdge take LRDIMM?
No. 16th and 17th generation servers take RDIMM only. High capacities use 128GB and 256GB RDIMMs instead.
Will the server log a warning with non-Dell memory?
No. iDRAC and the BIOS report the module as installed and run it at spec. There is no vendor lock on PowerEdge memory.
Can I add to the memory already installed?
Yes, when type, capacity, speed and rank match the installed modules, which iDRAC shows. If the existing set is small and mismatched, replacing it with a matched kit is usually cheaper than working around it.
Can I mix different capacity DIMMs in a PowerEdge?
Often, within limits that depend on the model. On the PowerEdge R750, Dell allows different capacities when the other population rules are met, with a limit of two capacities in one system. Check the manual for your model before mixing.
Why does my 14th generation PowerEdge say no memory is detected after a DIMM upgrade?
Dell's support article ties the message to a mismatch between the processor and the memory specification. On first generation Xeon Scalable (Skylake) processors, Dell says 8 GB density memory is required and 16 GB density modules are not expected to work. See also our server boot troubleshooting guide.
Dell PowerEdge memory for IT teams and fleets
NEMIX RAM is a US-based memory specialist, in business since 1993. Every PowerEdge module is researched, matched, and compatibility-tested by NEMIX RAM, is JEDEC-compliant, and is backed by a lifetime warranty. Purchase orders, net terms and volume pricing are available for IT teams, resellers, and government and education buyers. Request a quote with your models or Service Tags and quantities, or contact our sales team. You can also browse memory by manufacturer.
NEMIX RAM is an independent memory supplier and is not affiliated with Dell Technologies. Dell, PowerEdge, iDRAC, OpenManage, Intel, Xeon, AMD, EPYC, VMware, Hyper-V and SAP HANA are trademarks of their respective owners, used here only to identify compatible systems.