Dell PowerEdge memory compatibility is generation-, model- and configuration-dependent. Every PowerEdge generation in this guide uses a different DDR generation, DIMM count, or speed ceiling than the one before it, and none of them share compatible memory. This guide explains what each generation supports at the platform level. For a specific system's exact compatible modules and current pricing, use the TekBoost RAM Advisor.
Quick generation table
| Generation | Representative models | Memory type | DIMM slots | Maximum memory | Maximum speed | Key notes |
|---|---|---|---|---|---|---|
| 13G | R430, R630, R730/R730XD | DDR4 RDIMM/LRDIMM | 24 | 768 GB | Up to 2133 MT/s | UDIMM not supported |
| 14G | R440, R640, R740/R740XD | DDR4 RDIMM/LRDIMM/NVDIMM-N/DCPMM | 24 | 3 TB (7.68 TB with DCPMM+LRDIMM) | Up to 2933 MT/s | Up to 6 Optane PMem modules per socket |
| 15G | R450, R650, R750/R750xa/R750xs, T550 | DDR4 RDIMM/LRDIMM + Optane PMem 200 Series | 32 | RDIMM 2 TB / LRDIMM 8 TB (+ up to 16 PMem, 8 TB) | Up to 3200 MT/s | PMem continues from 14G |
| 16G | R660/R660xs, R760/R760xs, T560 | DDR5 RDIMM | 32 | 8 TB | Up to 4800 MT/s (4th Gen) or 5600 MT/s (5th Gen) at 1 DIMM/channel; 4400 MT/s at 2/channel | No persistent-memory support |
No generation in this table shares a memory type, DIMM count, or speed ceiling with another.
Dell 13G memory compatibility
13G PowerEdge servers (R430, R630, R730/R730XD) use DDR4 RDIMM or LRDIMM; Dell's own R630 Technical Guide explicitly states that unbuffered DIMMs (UDIMMs) are not supported. The R630 supports 24 DIMM slots, up to 768 GB, at speeds up to 2133 MT/s depending on the installed DIMM type and population.
Dell 14G memory compatibility
14G PowerEdge servers (R440, R640, R740/R740XD) use DDR4 RDIMM, LRDIMM, NVDIMM-N, or Intel Optane DC Persistent Memory, across 24 DIMM slots. The R640 and R740 both support up to 3 TB of DRAM, or up to 7.68 TB when DCPMM and LRDIMM are installed together, at speeds up to 2933 MT/s. Both platforms support up to 6 Optane DC Persistent Memory modules per processor socket, up to 12 in a 2-socket configuration.
Dell 15G memory compatibility
15G PowerEdge servers (R450, R650, R750/R750xa/R750xs, T550) use DDR4 RDIMM or LRDIMM across 32 DIMM slots on the R650 and R750, supporting up to 2 TB with RDIMM or 8 TB with LRDIMM, at speeds up to 3200 MT/s. 15G continues persistent-memory support with up to 16 Intel Optane Persistent Memory 200 Series modules.
Dell 16G memory compatibility
16G PowerEdge servers (R660/R660xs, R760/R760xs, T560) move to DDR5 RDIMM across 32 DIMM slots, up to 8 TB. Speed depends on both the installed CPU generation and DIMM population: Dell's own R760 Technical Guide states up to 4800 MT/s on 4th Generation Xeon Scalable processors or 5600 MT/s on 5th Generation, both at one DIMM per channel, dropping to 4400 MT/s at two DIMMs per channel for either CPU generation. 16G does not support Intel Optane Persistent Memory — Dell's own side-by-side comparison of the R760 against the R750 lists persistent memory for the R750 only, not for the R760.
RDIMM vs LRDIMM
RDIMM (registered DIMM) and LRDIMM (load-reduced DIMM) are both supported across 13G through 15G, with LRDIMM generally enabling a higher maximum capacity per slot than RDIMM on the same platform — confirmed directly on 15G, where Dell states a 2 TB RDIMM ceiling against an 8 TB LRDIMM ceiling for the same DIMM count. 16G, per Dell's own R760 documentation reviewed for this guide, lists RDIMM only.
DIMM population rules
Dell's R630 Technical Guide (13G) states explicit population rules: DIMMs with x4 and x8 data widths can be mixed, the largest-capacity DIMM must be installed first, and a system may contain a maximum of two different DIMM capacities and two different ranks. The R640, R740, R650, R750, and R760 Technical Guides reviewed for this guide do not state population rules in a comparable form. Confirm population requirements for 14G through 16G against the specific model's own documentation or the RAM Advisor before mixing DIMM capacities.
Memory speed limitations
Installed memory runs at the lower of the DIMM's rated speed and the speed the installed processor and population supports — a faster-rated DIMM does not exceed the processor's own ceiling. This is confirmed directly on 16G, where Dell's own documentation publishes two different maximum speeds for the same DIMM count depending on whether 1 or 2 DIMMs per channel are populated. For a specific system, the RAM Advisor separates a module's rated speed from its actual effective speed on that exact configuration.
Dual-socket population guidance
On dual-socket PowerEdge models, memory is generally populated per processor, and Dell's own persistent-memory figures scale directly with socket count — for example, 14G's Optane DC Persistent Memory allowance is stated per socket and doubles in a 2-socket configuration. Confirm the exact per-socket DIMM channel count and population order for a specific model before populating both sockets.
Cross-generation memory compatibility
No DDR generation in this guide is backward- or forward-compatible with another PowerEdge generation. 13G through 15G use DDR4; only 16G uses DDR5. A 14G DIMM cannot be used in a 15G server, and a 15G DIMM cannot be used in a 16G server, regardless of physical fit, because each generation's memory controller is built for a specific DDR generation and speed range.
Model-specific references
- Dell PowerEdge R640 specifications and options
- Dell PowerEdge R740 specifications and options
- Dell PowerEdge R650 specifications and options
- Dell PowerEdge R750 specifications and options
- Dell PowerEdge 13G vs 14G vs 15G vs 16G Guide
- Dell PowerEdge CPU Compatibility Guide
Use the RAM Advisor
This guide covers platform-level memory compatibility by generation. For a model-specific memory configuration, exact compatible modules, and current pricing, use the TekBoost RAM Advisor.
Configure / shop options
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Hardware bought from TekBoost carries our standard 3-year warranty with Next Business Day part replacement, subject to the terms, exclusions and conditions on that page. Every system is tested before shipment. To confirm an exact memory configuration against current stock, request a quote.
Methodology and sources
Last reviewed: 2026-11-13. Memory type, DIMM count, capacity, and speed figures are drawn directly from Dell's official Technical Guides for the R630 (Rev 1.6, 2015), R640, R740/R740XD, R650, R750, and R760 (Regulatory Model E82S Series, Rev. A06), each read and searched in full for this guide. Where Dell's own documentation does not state DIMM population rules in a comparable form — 14G through 16G in this guide — that field is omitted rather than estimated. The finding that 16G does not support Intel Optane Persistent Memory is drawn directly from Dell's own side-by-side R760-vs-R750 comparison table in the R760 Technical Guide.