16GB DDR4-2666 RDIMM vs 32GB DDR4-2133 LRDIMM
The 16GB DDR4-2666 RDIMM and the 32GB DDR4-2133 LRDIMM are both server memory modules we supply tested from Hong Kong, and the figures below are the same ones published on each product page. They share 4 listed specification rows and separate on capacity, speed, organisation, so the decision is less about "which is better" and more about which of those differences your platform or workload can actually use.
Nothing on this page is a price: component pricing moved too fast in 2026 for a printed figure to stay honest, so both are quoted on request against confirmed stock with the date the quote holds until. If you are replacing a part, send the platform and we will confirm the population before you commit.
Side by side
16GB DDR4-2666 RDIMM vs 32GB DDR4-2133 LRDIMM specifications
| Specification | 16GB DDR4-2666 RDIMM | 32GB DDR4-2133 LRDIMM |
|---|---|---|
| Capacity | 16GB | 32GB |
| Speed | DDR4-2666, PC4-21300 | DDR4-2133, PC4-17000 |
| Organisation | 2Rx8 (dual rank, x8 DRAMs) | 4Rx4 (quad rank, x4 DRAMs) |
| Form Factor | RDIMM, 288-pin, DDR4 | LRDIMM, 288-pin, DDR4 |
| Error Correction | ECC registered, with on-DIMM register and PLL | ECC, load-reduced |
| Intel Platforms | Xeon Scalable 1st Gen (Skylake-SP) at 2666; 2nd Gen boards run it at 2666 | Xeon E5-2600 v3 (Haswell) and v4 (Broadwell) |
| AMD Platforms | EPYC 7001 (Naples) at 2666 | not stated |
| Voltage | 1.2V (JEDEC DDR4 standard) | 1.2V (JEDEC DDR4 standard) |
| DRAM | Samsung / SK hynix / Micron depending on lot - confirmed at quote | Samsung / SK hynix / Micron depending on lot - confirmed at quote |
| Condition | New, or decommissioned pulls - stated line by line before you order | New, or decommissioned pulls - stated line by line before you order |
| Warranty | 1 year, in writing, confirmed with the order | 1 year, in writing, confirmed with the order |
| Compatibility | not stated | Requires a platform that supports LRDIMM - not interchangeable with RDIMM in the same channel |
Rows that differ are highlighted. Figures are the same ones published on each product page; where a figure is community-sourced rather than vendor-published it is stated on that page. Confirm every part against your build sheet when ordering.
Where they differ
- ·32GB DDR4-2133 LRDIMM has the higher capacity (32 vs 16); 16GB DDR4-2666 RDIMM trades that for something else.
- ·Speed — 16GB DDR4-2666 RDIMM: DDR4-2666, PC4-21300; 32GB DDR4-2133 LRDIMM: DDR4-2133, PC4-17000.
- ·Organisation — 16GB DDR4-2666 RDIMM: 2Rx8 (dual rank, x8 DRAMs); 32GB DDR4-2133 LRDIMM: 4Rx4 (quad rank, x4 DRAMs).
- ·Form Factor — 16GB DDR4-2666 RDIMM: RDIMM, 288-pin, DDR4; 32GB DDR4-2133 LRDIMM: LRDIMM, 288-pin, DDR4.
- ·Error Correction — 16GB DDR4-2666 RDIMM: ECC registered, with on-DIMM register and PLL; 32GB DDR4-2133 LRDIMM: ECC, load-reduced.
- ·Intel Platforms — 16GB DDR4-2666 RDIMM: Xeon Scalable 1st Gen (Skylake-SP) at 2666; 2nd Gen boards run it at 2666; 32GB DDR4-2133 LRDIMM: Xeon E5-2600 v3 (Haswell) and v4 (Broadwell).
What they share
Voltage: 1.2V (JEDEC DDR4 standard); DRAM: Samsung / SK hynix / Micron depending on lot - confirmed at quote; Condition: New, or decommissioned pulls - stated line by line before you order; Warranty: 1 year, in writing, confirmed with the order.
Decision
Which one to buy
Memory choices are governed by the platform first and the price second. Capacity per module decides how far a fixed number of slots can go; rated speed decides the channel ceiling, but only if the CPU and the rest of the population can hold it; type (RDIMM versus LRDIMM) decides whether the module will train at all, because the two cannot share a channel. Work out the per-channel population you need first, then choose the module that reaches it within the platform's rank limit — a larger module is not automatically the better buy if the resulting population runs at a lower speed.
Choose the 16GB DDR4-2666 RDIMM if
- ·Organisation: 2Rx8 (dual rank, x8 DRAMs)
- ·Form Factor: RDIMM, 288-pin, DDR4
- ·Error Correction: ECC registered, with on-DIMM register and PLL
Choose the 32GB DDR4-2133 LRDIMM if
- ·You need more capacity — the 32GB DDR4-2133 LRDIMM lists 32GB against 16GB on the 16GB DDR4-2666 RDIMM.
- ·Organisation: 4Rx4 (quad rank, x4 DRAMs)
- ·Form Factor: LRDIMM, 288-pin, DDR4
Photos
What the two look like
16GB DDR4-2666 RDIMM
Photo from the 16GB DDR4-2666 RDIMM page. Every unit's label is read against your order before dispatch.
32GB DDR4-2133 LRDIMM
Photo from the 32GB DDR4-2133 LRDIMM page. Every unit's label is read against your order before dispatch.
Frequently asked questions
How much do the 16GB DDR4-2666 RDIMM and the 32GB DDR4-2133 LRDIMM cost?
We do not publish prices for either: DRAM and CPU pricing moved too fast in 2026 for a printed figure to stay honest. Send the quantity, the platform and the condition you want and we quote both against confirmed stock, with the date the figure holds until.
What is the main difference between the 16GB DDR4-2666 RDIMM and the 32GB DDR4-2133 LRDIMM?
Capacity (16GB DDR4-2666 RDIMM: 16GB; 32GB DDR4-2133 LRDIMM: 32GB); Speed (16GB DDR4-2666 RDIMM: DDR4-2666, PC4-21300; 32GB DDR4-2133 LRDIMM: DDR4-2133, PC4-17000); Organisation (16GB DDR4-2666 RDIMM: 2Rx8 (dual rank, x8 DRAMs); 32GB DDR4-2133 LRDIMM: 4Rx4 (quad rank, x4 DRAMs)).
Can I use the 16GB DDR4-2666 RDIMM and the 32GB DDR4-2133 LRDIMM in the same system?
Only within a supported population. The platform must accept both module types (RDIMM, 288-pin, DDR4 vs LRDIMM, 288-pin, DDR4), and LRDIMM and RDIMM cannot share a channel. Tell us the platform and we will check the population before shipping.
Which one should I buy?
Buy the one whose strong points match the job: see the "Choose" section above. If you are replacing an existing part, send the platform or the old part number and we will confirm compatibility before you order.
What condition are they in, and do you ship worldwide?
Both are supplied tested with a 1-year written warranty. Condition is stated line by line before you order — new, decommissioned pull or OEM tray — and we ship worldwide from the Hong Kong warehouse with full export documentation, typically 3–7 days by air.
Get a quote for either — or both
Tell us the quantity, the platform and the condition you need. We confirm stock and put a firm figure in writing with the date it holds until.
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