Best RDIMM DDR4 RAMS in 2026: 15 Picks Ranked by Specs
As an Amazon Associate we earn from qualifying purchases. Links on this page are affiliate links.
Finding the best RDIMM ddr4 RAMs requires matching server specifications precisely. We compared 15 options ranked strictly by published specs. The top pick, Micron 64GB 3200MHz DDR4 RDIMM, leads with 64GB capacity and 3200MHz speed for high-density upgrades. All selections focus on form factor, speed, and capacity data from the listings. This guide helps you decide which registered memory fits your specific server infrastructure needs.
Quick picks
The best fit for you
- You need maximum density per slot on DDR4 platforms Micron 64GB 3200MHz DDR4 RDIMM This module provides 64GB capacity running at 3200MHz for high-density server upgrades.
- You want a dual-channel kit for balanced capacity Crucial 64GB (2x32GB) 2666MHz DDR4 RDIMM This kit includes two 32GB modules running at 2666MHz for dual-channel operation.
- You need a single module for low-density upgrades SK Hynix 16GB DDR4 2666MHz ECC RDIMM This 16GB stick runs at 2666MHz for moderate-density server replacements.
- You require a full eight-module set for multi-channel layouts Samsung 256GB (8x32GB) DDR4 2666MHz RDIMM Kit This kit contains eight 32GB modules totaling 256GB at 2666MHz.
Our 15 picks
Micron 64GB 3200MHz DDR4 RDIMM
Best for: high-density 3200MHz server upgrades
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 64GB
- Height
- 0.48 inches
- Length
- 2.07 inches
- Weight
- 1.12 ounces
View on Amazon: Micron 64GB 3200MHz DDR4 RDIMM Affiliate link
This Micron module gives you 64GB of memory on a single registered DIMM running at 3200MHz. It uses a 2Rx4 organization and standard RDIMM architecture for server motherboards requiring DDR4 memory. You will find it suits high-density workstation or enterprise server builds where slot limits make maximum module size and 3200MHz clock speeds necessary.
Pros
- 64GB capacity on a single stick
- 3200MHz memory speed
- Dual-rank 2Rx4 registered design
Cons
- CAS latency is not listed in the specifications
- Operating voltage is not specified in the product data
Good fit if
- You need 64GB of memory in a single slot
- You run server hardware compatible with 3200MHz RDIMMs
Skip if
- You need a multi-channel kit in a single package
- You use a desktop motherboard that requires unbuffered DIMMs
Verdict: Micron 64GB 3200MHz DDR4 RDIMM provides dense single-module capacity running at 3200MHz. It fits administrators who need maximum memory density per slot on DDR4 platforms.
SK Hynix 32GB DDR4-2133 RDIMM
Best for: Server systems requiring ECC and 2133MHz speed
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 32GB
- Memory Speed
- 2133 MHz
- Module Configuration
- 1x32GB
- ECC Support
- ECC RDIMM
- Dimensions
- 5.25 × 0.16 × 1.21 inches
View on Amazon: SK Hynix 32GB DDR4-2133 RDIMM Affiliate link
This SK Hynix module offers 32GB of capacity on a 288-pin RDIMM form factor. It runs at 2133MHz with PC4-17000P speed and includes ECC support for error correction. The 4RX4 configuration is designed for server environments. You need this kit if your system requires registered memory with error checking capabilities for stable operation.
Pros
- 32GB total memory capacity
- DDR4-2133 speed rating
- ECC support for data integrity
- RDIMM form factor
Cons
- Lower 2133MHz speed compared to 2666MHz or 3200MHz options
- 4RX4 configuration may limit compatibility with some motherboards
- Single stick capacity is modest for high-density builds
Good fit if
- You need ECC-registered memory for server stability
- Your motherboard supports 4RX4 DIMM configurations
- You are upgrading a system that uses DDR4-2133
Skip if
- You require speeds higher than 2133MHz
- Your system only supports unregistered non-ECC RAM
- You need 64GB capacity in a single stick
Verdict: SK Hynix 32GB DDR4-2133 RDIMM fits servers needing reliable ECC memory at standard speeds. It is a solid choice for legacy or specific server builds that do not require higher bandwidth.
Crucial 64GB (2x32GB) 2666MHz DDR4 RDIMM
Best for: dual-channel servers needing balanced 64GB capacity
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 64GB
- Memory Speed
- 2666 MT/S
- CAS Latency
- CL19
- Voltage
- 1.2V
- Module Configuration
- 2X 32GB
View on Amazon: Crucial 64GB (2x32GB) 2666MHz DDR4 RDIMM Affiliate link
This Crucial dual-channel memory kit delivers 64GB of total capacity across two 32GB registered RDIMMs. It operates at 2666 MT/s with CL19 latency and draws standard 1.2V power. The 288-pin ECC registered modules prevent data corruption during continuous workloads. You will find it suitable for compatible server boards that require balanced two-module DDR4 memory configurations.
Pros
- Total 64GB capacity split across two 32GB modules
- Registered ECC support for system stability
- Standard low-energy 1.2V operation
- 2666 MT/s memory transfer speed
Cons
- Lower 2666 MT/s speed than 3200 MT/s RDIMMs
- Occupies two motherboard slots rather than a single 64GB DIMM
- Higher CL19 latency compared to CL17 alternatives
Good fit if
- You need a matched pair of 32GB RDIMMs for dual-channel server boards.
- You run enterprise hardware designed for 2666 MT/s DDR4 specifications.
- You require registered ECC error correction at standard 1.2V power.
Skip if
- You need peak data bandwidth from 3200 MT/s memory modules.
- You want a single 64GB module to preserve open slots for expansion.
- You require higher overall density like 128GB or 256GB bundles.
Verdict: Crucial 64GB (2x32GB) 2666MHz DDR4 RDIMM Kit fits enterprise administrators upgrading server memory with balanced two-channel registered modules. It provides stable 1.2V multi-channel operation on platforms limited to 2666 MT/s DDR4 speeds.
SK Hynix 16GB DDR4 2400MHz ECC RDIMM
Best for: 2400MHz DDR4 server memory replacements
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 16GB
- Memory Speed
- 2400MHz
- CAS Latency
- CL17
- Voltage
- 1.2V
- Module Configuration
- 1x16GB
View on Amazon: SK Hynix 16GB DDR4 2400MHz ECC RDIMM Affiliate link
This is an SK Hynix 16GB registered memory module built for systems requiring DDR4 server RAM. You get a 2400MHz operating frequency, CAS latency of 17, and standard 1.2V power consumption. With its 288-pin RDIMM design and ECC support, it matches workstations and server boards tailored for PC4-19200 specifications needing reliable error-checking capacity.
Pros
- Operates at 1.2V standard DDR4 voltage
- Features registered ECC support for error correction
- CL17 CAS latency at 2400MHz
- Standard 288-pin RDIMM server form factor
Cons
- 2400MHz speed is lower than 2666MHz and 3200MHz alternatives
- 16GB capacity provides less density than 32GB or 64GB options
Good fit if
- You require registered ECC memory for a 2400MHz server platform.
- You need a single 16GB DDR4 module running at 1.2V.
Skip if
- You need higher bandwidth options like DDR4-2666 or DDR4-3200.
- You want higher-density 32GB or 64GB modules to maximize motherboard slots.
Verdict: SK Hynix 16GB DDR4 2400MHz RDIMM fits server administrators maintaining DDR4-2400 platforms that require registered error-correcting memory at standard 1.2V.
SK Hynix 32GB DDR4 ECC RDIMM
Best for: 2666MHz server platforms needing 32GB modules
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 32GB
- Memory Speed
- 2666 MT/s
- ECC Support
- ECC
- Dimensions
- 9 × 6 × 4 inches
View on Amazon: SK Hynix 32GB DDR4 ECC RDIMM Affiliate link
This SK Hynix module gives you 32GB of DDR4 server memory in a standard RDIMM form factor. Running at PC4-2666V speeds with a 2Rx4 dual-rank configuration, it provides registered ECC support to catch memory errors in compatible systems. It suits you if you need a dependable single-module memory expansion for enterprise boards running 2666MHz DDR4 RDIMMs.
Pros
- 32GB capacity on a single RDIMM module
- PC4-2666V (PC4-21300) transfer rate
- Registered ECC architecture for server stability
- 2Rx4 dual-rank organization
Cons
- 2666MHz clock speed is lower than 3200MHz options on the list
- Single-stick 32GB capacity provides less volume than 64GB modules or multi-pack bundles
Good fit if
- You need a single 32GB 2Rx4 registered ECC module for a server motherboard.
- You operate a platform built specifically for DDR4-2666 memory speeds.
Skip if
- You need higher memory throughput from 3200MHz DDR4 RDIMMs.
- You require high-density memory pools via 64GB sticks or multi-module bundles.
Verdict: SK Hynix 32GB DDR4-2666 ECC RDIMM matches systems needing a balanced 32GB dual-rank expansion at 2666MHz. It delivers standard registered ECC server performance for administrators upgrading compatible DDR4 platforms.
Samsung 32GB DDR4 ECC RDIMM
Best for: 2666MHz DDR4 server memory expansions
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 32GB
- Memory Speed
- 2666 MT/s
- ECC Support
- ECC
- Compatible Device
- Server
View on Amazon: Samsung 32GB DDR4 ECC RDIMM Affiliate link
This Samsung module delivers 32GB of DDR4 server memory in a registered RDIMM form factor. It operates at PC4-2666V speeds with a dual-rank 2Rx4 layout and registered ECC support. You get error correction designed specifically for server motherboards. It suits you if you need to upgrade or expand an existing DDR4-2666 server with a single 32GB stick.
Pros
- 32GB capacity on a single module
- PC4-2666V operating speed
- ECC support for data error correction
- 2Rx4 dual-rank architecture
Cons
- Lower 2666MHz frequency than available 3200MHz RDIMMs
- Single-stick package provides no multi-channel pairing out of the box
Good fit if
- You need a single 32GB DDR4 module rated for 2666MHz server platforms.
- You run server hardware requiring 2Rx4 registered ECC memory.
Skip if
- You require faster 3200MHz transfer speeds for your workload.
- You want a matched multi-module kit in a single package.
Verdict: Samsung 32GB DDR4 2666MHz RDIMM fits server administrators who need genuine 2666MHz registered ECC modules to maintain or expand compatible infrastructure.
Samsung 32GB DDR4 ECC RDIMM
Best for: Servers requiring 2666MHz CL19 registered DDR4 memory
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 32GB
- Memory Speed
- 2666
- CAS Latency
- CL19
- ECC Support
- ECC
- Compatible Device
- Server
View on Amazon: Samsung 32GB DDR4 ECC RDIMM Affiliate link
This Samsung server memory module offers 32GB of DDR4 capacity running at 2666MHz. It features ECC registered architecture with a CAS latency of CL19 and a 2Rx4 rank configuration. If your server requires PC4-21300 RDIMM hardware, this single-module stick gives you stable system memory designed strictly for compatible server platforms without unnecessary configuration steps.
Pros
- 32GB capacity on a single RDIMM stick
- 2666MHz operating speed with PC4-21300 bandwidth
- ECC registered support for server stability
- 2Rx4 dual-rank layout with CL19 latency
Cons
- 2666MHz clock speed is lower than 3200MHz options on the list
- 32GB module provides less density than 64GB RDIMMs
Good fit if
- You need a single 32GB DDR4 RDIMM running at 2666MHz.
- You require ECC registered memory with CL19 latency for a server build.
Skip if
- You need faster 3200MHz memory speeds for your server architecture.
- You want higher per-slot capacity from a 64GB module.
Verdict: Samsung 32GB DDR4-2666 ECC RDIMM suits server operators who need standard 2666MHz CL19 registered memory to populate individual DIMM slots.
SK Hynix 16GB DDR4 2666MHz ECC RDIMM
Best for: low-density DDR4 server upgrades and replacements
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 16GB
- Memory Speed
- 2666 MT/s
- CAS Latency
- CL19
- ECC Support
- ECC
- Compatible Device
- Server
View on Amazon: SK Hynix 16GB DDR4 2666MHz ECC RDIMM Affiliate link
This SK Hynix module gives you 16GB of registered DDR4 server memory running at 2666MHz. It features error-correcting code (ECC) support with a CL19 CAS latency on an RDIMM form factor. If you need a single 16GB stick to populate an open server channel or replace an individual module, this fits standard DDR4 enterprise boards.
Pros
- 2666MHz operating frequency (PC4-21300)
- ECC registered reliability for enterprise servers
- Standard RDIMM form factor with CL19 latency
Cons
- Modest 16GB capacity compared to 32GB and 64GB options
- Slower memory clock than 3200MHz DDR4 modules
Good fit if
- You need a single 16GB replacement RDIMM for a 2666MHz server.
- You want basic ECC registered memory without excess module capacity.
Skip if
- You need high-density 32GB or 64GB sticks for memory-heavy virtualization.
- You run a server platform optimized for 3200MHz DDR4 throughput.
Verdict: SK Hynix 16GB 2666MHz DDR4 RDIMM fits server administrators who need a single, moderate-density ECC replacement stick running at baseline 2666MHz speeds. It meets exact manufacturer specifications for systems that do not require 32GB or 64GB densities.
A-Tech 16GB DDR4 2666MHz ECC RDIMM
Best for: Hynix 16GB 2666MHz server memory replacement
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 16GB
- Memory Speed
- 2666 MHz
- Voltage
- 1.2V
- Module Configuration
- 1x16GB
- ECC Support
- ECC
View on Amazon: A-Tech 16GB DDR4 2666MHz ECC RDIMM Affiliate link
This A-Tech memory module gives you a 16GB DDR4 registered DIMM running at 2666MHz. Operating at 1.2 volts with a 288-pin RDIMM form factor, it includes ECC support to protect against data corruption. It suits you if you need a direct replacement module for specific Hynix server memory configurations without changing your existing server operating voltage or timing.
Pros
- Operates at standard 1.2V DDR4 voltage
- 2666MHz operating speed with PC4-21300 rating
- ECC RDIMM design for server data integrity
- Direct specification match for Hynix HMA82GR7CJR8N-VK
Cons
- 16GB capacity is lower than the 32GB and 64GB options on this list
- 2666MHz clock speed is lower than 3200MHz alternatives
Good fit if
- You need a 16GB DDR4 2666MHz replacement for a Hynix HMA82GR7CJR8N-VK module.
- You require 1.2V registered ECC memory for an enterprise server board.
Skip if
- You need higher per-slot density like 32GB or 64GB modules.
- You run server workloads that require 3200MHz DDR4 memory speeds.
Verdict: A-Tech 16GB DDR4 2666MHz ECC RDIMM serves system administrators replacing single Hynix modules in 2666MHz server environments. It provides exact 1.2V RDIMM operating parameters for matching existing server memory ranks.
A-Tech 32GB DDR4-2133 ECC RDIMM
Best for: Legacy server upgrades requiring ECC stability
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 32GB
- Memory Speed
- 2133 MHz
- Voltage
- 1.2V
- Module Configuration
- 1x32GB
- ECC Support
- ECC
View on Amazon: A-Tech 32GB DDR4-2133 ECC RDIMM Affiliate link
This A-Tech module is a 32GB DDR4 RDIMM running at 2133MHz. It uses 1.2V voltage and includes ECC support for server reliability. The kit replaces the Samsung M393A4K40BB0-CPB. You need this if your system requires registered memory with error correction. It fits standard 288-pin slots. This is a solid option for older server platforms that do not support higher speeds.
Pros
- 32GB capacity per module
- 2133MHz base speed
- ECC error correction support
- 1.2V low voltage operation
- Registered DIMM form factor
Cons
- 2133MHz speed is slower than many alternatives
- Single module capacity is modest for high-end builds
- No mention of specific latency timings
Good fit if
- You are upgrading an older server system
- You need ECC memory for data integrity
- You require 32GB modules for specific slot configurations
Skip if
- You need speeds above 2133MHz
- You are building a modern high-performance workstation
- You require non-ECC UDIMM memory
Verdict: A-Tech 32GB DDR4-2133 ECC RDIMM is a reliable choice for legacy server environments. It suits users who prioritize stability and compatibility over raw speed. This module ensures your older hardware runs correctly without needing faster, incompatible parts.
A-Tech 32GB DDR4 2666MHz ECC RDIMM
Best for: replacing single 32GB 2666MHz server RDIMMs
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 32GB
- Memory Speed
- 2666 MHz
- Voltage
- 1.2V
- Module Configuration
- 1x32GB
- ECC Support
- ECC
View on Amazon: A-Tech 32GB DDR4 2666MHz ECC RDIMM Affiliate link
This module is a 32GB DDR4 registered memory stick operating at 2666MHz with a 1.2V profile. Designed as a 288-pin ECC RDIMM, it delivers server-grade error correction and stability. You get a direct replacement unit for systems requiring 2Rx4 dual-rank modules. It suits your build if you need to maintain or expand 2666MHz enterprise server memory.
Pros
- 32GB capacity on a single 288-pin RDIMM module
- 2666MHz operating frequency at 1.2V
- ECC Registered memory for error-correction support
- 2Rx4 dual-rank architecture
Cons
- 2666MHz clock speed is lower than 3200MHz alternatives
- Single-module pack provides less total density than multi-module kits
Good fit if
- You need a 32GB 2666MHz ECC RDIMM for server expansion.
- You require a 2Rx4 dual-rank 1.2V DDR4 module replacement.
Skip if
- You require higher memory bandwidth like 3200MHz DDR4.
- You need high-capacity multi-stick bundles exceeding 32GB.
Verdict: A-Tech 32GB 2666MHz DDR4 RDIMM delivers standard 1.2V ECC registered operation for system administrators replacing individual 2666MHz server modules.
Crucial 64GB DDR4 2666MHz ECC RDIMM Kit
Best for: dual-channel 2666MHz server memory upgrades
- Form Factor
- RDIMM (what this guide is about)
- Module Configuration
- 4x32GB
- ECC Support
- ECC
- Memory Speed
- 2666MHz
- Size
- 64GB
View on Amazon: Crucial 64GB DDR4 2666MHz ECC RDIMM Kit Affiliate link
This Crucial server memory package provides 64GB of registered ECC DDR4 SDRAM split across two 32GB sticks. It operates at 2666MHz with a PC4-21300 bandwidth rating in a dual-rank layout. You get multi-channel capability right away, making it suitable if your workstation or server board requires matched pairs for dual-channel memory channels.
Pros
- 64GB total capacity split across two 32GB modules
- Registered ECC error correction
- 2666MHz memory speed (PC4-21300)
- Dual-rank design
Cons
- 2666MHz clock speed trails 3200MHz RDIMM options on the list
- Occupies two DIMM slots instead of a single 64GB module
Good fit if
- You need a 64GB matched pair of registered ECC DDR4 modules for a dual-channel board.
- You run a server platform rated specifically for 2666MHz RDIMM operation.
Skip if
- You want faster 3200MHz transfer speeds supported by your processor.
- You need to conserve open DIMM slots by using a single 64GB module.
Verdict: Crucial 64GB 2666MHz DDR4 RDIMM Kit delivers 64GB across two registered modules for servers that require 2666MHz dual-rank memory across twin slots.
Nemix RAM 32GB DDR4 2400MHz ECC RDIMM
Best for: 2400MHz DDR4 server memory replacements
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 32GB
- Memory Speed
- 2400 MT/s
- CAS Latency
- CL17
- Voltage
- 1.2V
- Module Configuration
- 1x32GB
View on Amazon: Nemix RAM 32GB DDR4 2400MHz ECC RDIMM Affiliate link
This Nemix RAM module gives you 32GB of registered DDR4 memory running at 2400MHz. It operates at 1.2V with CL17 latency and a 2Rx4 dual-rank configuration on a standard 288-pin interface. You get integrated ECC to correct single-bit errors. It suits you if your server platform specifically requires PC4-19200 speeds without exceeding standard 1.2V power requirements.
Pros
- DDR4-2400 transfer rate with CL17 latency at 1.2V
- Dual-rank 2Rx4 registered ECC architecture
- Lifetime replacement warranty and technical support
Cons
- 2400MHz frequency is slower than 2666MHz or 3200MHz alternatives
- Single 32GB DIMM package rather than a multi-module kit
Good fit if
- You need a single 32GB DDR4 module rated for 2400MHz.
- You operate server hardware requiring 1.2V 2Rx4 registered memory.
Skip if
- You manage servers that take advantage of 2666MHz or 3200MHz speeds.
- You require a bundled multi-module kit to populate several memory channels at once.
Verdict: Nemix RAM 32GB DDR4 2400MHz ECC RDIMM provides an exact-specification replacement for servers needing 2400MHz PC4-19200 dual-rank registered memory.
Samsung 256GB (8x32GB) DDR4 2666MHz RDIMM Kit
Best for: eight-channel server systems needing 256GB memory
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 256GB
- Memory Speed
- 2666MHz
- CAS Latency
- CL 19
- Module Configuration
- 8 x 32GB
- ECC Support
- Registered
View on Amazon: Samsung 256GB (8x32GB) DDR4 2666MHz RDIMM Kit Affiliate link
This Samsung server memory kit delivers 256GB of total capacity through eight 32GB RDIMM modules. It operates at 2666MHz with a CAS latency of CL 19 across a standard 288-pin interface. You get high-density registered ECC memory designed for enterprise servers. It suits your setup if you need to populate multi-channel server boards with balanced memory.
Pros
- High 256GB total capacity across eight 32GB modules
- Registered RDIMM architecture for server stability
- Standard 288-pin DDR4 interface with CL 19 latency
Cons
- Requires eight open DIMM slots to deploy the full kit
- Not compatible with desktop motherboards
- Lower 2666MHz clock speed than 3200MHz options
Good fit if
- You run a server board with eight available RDIMM slots.
- You need 256GB of registered memory rated at 2666MHz.
Skip if
- You want memory for a standard consumer desktop system.
- You need higher bandwidth from 3200MHz DDR4 RDIMMs.
Verdict: Samsung 256GB 8x32GB DDR4 2666MHz RDIMM Kit fits enterprise server administrators who need a matching eight-module set for multi-channel memory layouts.
Samsung 64GB (2x32GB) 2666MHz DDR4 RDIMM
Best for: dual-channel 64GB DDR4 server memory upgrades
- Form Factor
- RDIMM (what this guide is about)
- Total Capacity
- 64GB
- Memory Speed
- 2666MHz
- CAS Latency
- CL 19
- Module Configuration
- 2 x 32GB
- ECC Support
- Registered
View on Amazon: Samsung 64GB (2x32GB) 2666MHz DDR4 RDIMM Affiliate link
This Samsung memory kit gives you 64GB of total server memory divided across two 32GB 288-pin RDIMMs. Running at 2666MHz with a CAS latency of CL19, it operates on standard DDR4 server boards. It suits you if your server platform requires registered ECC modules across a dual-channel setup without stepping up to larger bundles.
Pros
- 64GB capacity supplied as two 32GB modules
- 2666MHz speed rating (PC4-21300)
- Registered ECC RDIMM form factor
- CL19 CAS latency
Cons
- Lower 2666MHz clock speed than 3200MHz alternatives
- Incompatible with desktop motherboards
Good fit if
- You need a matched pair of 32GB registered RDIMMs for dual-channel server operation.
- You run a server board designed for 2666MHz PC4-21300 DDR4 memory.
Skip if
- You build or upgrade a standard desktop PC.
- You require faster memory frequencies such as 3200MHz.
Verdict: Samsung 64GB 2666MHz DDR4 RDIMM Kit provides a dual-stick registered ECC configuration tailored for servers needing 64GB of balanced system memory.
Specifications side by side
| Spec | Micron 64GB 3200MHz DDR4 RDIMM | SK Hynix 32GB DDR4-2133 RDIMM | Crucial 64GB (2x32GB) 2666MHz DDR4 RDIMM | SK Hynix 16GB DDR4 2400MHz ECC RDIMM | SK Hynix 32GB DDR4 ECC RDIMM | Samsung 32GB DDR4 ECC RDIMM | Samsung 32GB DDR4 ECC RDIMM | SK Hynix 16GB DDR4 2666MHz ECC RDIMM | A-Tech 16GB DDR4 2666MHz ECC RDIMM | A-Tech 32GB DDR4-2133 ECC RDIMM | A-Tech 32GB DDR4 2666MHz ECC RDIMM | Crucial 64GB DDR4 2666MHz ECC RDIMM Kit | Nemix RAM 32GB DDR4 2400MHz ECC RDIMM | Samsung 256GB (8x32GB) DDR4 2666MHz RDIMM Kit | Samsung 64GB (2x32GB) 2666MHz DDR4 RDIMM |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total Capacity | 64GB | 32GB | 64GB | 16GB | 32GB | 32GB | 32GB | 16GB | 16GB | 32GB | 32GB | not stated | 32GB | 256GB | 64GB |
| Memory Speed | not stated | 2133 MHz | 2666 MT/S | 2400MHz | 2666 MT/s | 2666 MT/s | 2666 | 2666 MT/s | 2666 MHz | 2133 MHz | 2666 MHz | not stated | 2400 MT/s | 2666MHz | 2666MHz |
| CAS Latency | not stated | not stated | CL19 | CL17 | not stated | not stated | CL19 | CL19 | not stated | not stated | not stated | not stated | CL17 | CL 19 | CL 19 |
| Voltage | not stated | not stated | 1.2V | 1.2V | not stated | not stated | not stated | not stated | 1.2V | 1.2V | 1.2V | not stated | 1.2V | not stated | not stated |
| Module Configuration | not stated | 1x32GB | 2X 32GB | 1x16GB | not stated | not stated | not stated | not stated | 1x16GB | 1x32GB | 1x32GB | 4x32GB | 1x32GB | 8 x 32GB | 2 x 32GB |
| Form Factor | RDIMM | U-DIMM | not stated | not stated | RDIMM | RDIMM | RDIMM | RDIMM | RDIMM | RDIMM | RDIMM | not stated | U-DIMM | RDIMM | RDIMM |
| ECC Support | not stated | ECC RDIMM | ECC | ECC REG | ECC | ECC | ECC | ECC | ECC | ECC | ECC | ECC | ECC | Registered | Registered |
| Height | 0.48 inches | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated |
| Compatible Device | not stated | not stated | not stated | not stated | not stated | Server | Server | Server | not stated | not stated | not stated | not stated | Server | Server | Server |
| Size | 64GB | 32GB | not stated | 16GB | 32GB | 32GB | 32GB | 16GB | 16GB | 32GB | 32GB | 64GB | 32GB | not stated | 64GB |
| Length | 2.07 inches | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated |
| Weight | 1.12 ounces | 1.12 ounces | 0.8 ounces | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | not stated | 2 ounces | not stated | not stated |
| Dimensions | not stated | 5.25 × 0.16 × 1.21 inches | 1.97 × 0.98 × 0.39 inches | not stated | 9 × 6 × 4 inches | not stated | not stated | not stated | 5.25 × 1.23 × 0.15 inches | 5.25 × 1.23 × 0.15 inches | 5.25 × 1.23 × 0.15 inches | not stated | not stated | not stated | not stated |
| Color | Multicolor | not stated | not stated | Multicolor | Multicolor | not stated | Multicolor | Multicolor | not stated | not stated | not stated | Multicolor | not stated | Multicolor | Multicolor |
| Model | MTA36ASF8G72PZ-3G2B2 | HMA84GL7MMR4N-TF | CT2K32G4RFD4266 | 8541593987 | 8541594394 | M393A4K40BB2-CTD | M393A4K40CB2-CTD7Q | HMA82GR7AFR8N-VK | HMA82GR7CJR8N-VK-ATC | M393A4K40BB0-CPB-ATC | M393A4K40BB2-CTD-ATC | RAMKit13A | M393A4K40BB1-CRC | ASIRAM22 | ASIRAM20 |
Because RDIMM modules require dedicated platform support, you must verify memory compatibility against specifications for the best DDR4 motherboards.
How to Choose RDIMM DDR4 RAM
-
Verify ECC Support
Server systems require Registered DIMMs with Error Correction Code. This feature detects and fixes data corruption, ensuring stability for critical workloads. All products in this guide support ECC. You must confirm your motherboard supports registered memory before purchasing. Modules like the SK Hynix 32GB DDR4-2133 RDIMM include this essential protection. Without ECC, your server may experience silent data errors. Always check the attributes list for ECC support to avoid compatibility issues with your enterprise hardware.
-
Match Memory Speed
Your server’s chipset determines the maximum supported speed. Common DDR4 speeds include 2133, 2400, and 2666 MT/s. Installing faster modules, like the Micron 64GB 3200MHz RDIMM, may result in the system running them at a lower, supported speed. Check your motherboard manual for the rated MT/s. The Samsung 32GB DDR4 2666MHz RDIMM fits systems limited to that frequency. Matching the speed ensures optimal performance without instability or boot failures. Do not assume higher numbers mean better speed in all server contexts.
-
Check Module Capacity
RDIMM capacity affects how much total memory you can install. Single modules range from 16GB to 64GB. The Micron 64GB 3200MHz DDR4 RDIMM offers high density per slot. This allows you to fill fewer slots for large total capacity. Lower density options, like the SK Hynix 16GB DDR4 2400MHz ECC RDIMM, are useful for filling remaining slots or budget builds. Consider your server’s total memory requirement. Higher capacity modules may cost more but reduce the number of slots needed. Plan your layout based on available DIMM slots and total RAM needs.
-
Confirm Voltage Requirements
Standard DDR4 RDIMMs operate at 1.2V. This is the baseline voltage for most modern server platforms. Some modules explicitly list 1.2V in their attributes, such as the Crucial 64GB (2x32GB) 2666MHz DDR4 RDIMM Kit. Ensure your server supports this voltage. Using incorrect voltage can cause instability or hardware damage. Most listed products adhere to this standard. Verify the voltage specification if your server uses older or specialized hardware. Consistency in voltage across all installed modules is crucial for stable operation. Do not mix voltages unless explicitly supported by the manufacturer.
-
Assess CAS Latency
CAS Latency (CL) measures the delay before data is accessed. Lower numbers indicate faster response times. For example, the SK Hynix 16GB DDR4 2400MHz ECC RDIMM has a CL17 rating. The Crucial 64GB (2x32GB) 2666MHz DDR4 RDIMM Kit features CL19. While speed is important, latency also impacts performance. Match the latency to your workload requirements. Lower latency is beneficial for tasks requiring quick data retrieval. However, higher speed modules often have higher latency numbers. Compare CL values when choosing between modules of similar speeds. It provides a clearer picture of actual performance characteristics.
Frequently asked questions
What is the highest speed available for DDR4 RDIMM?
The highest speed available in this list is 3200MHz. The Micron 64GB 3200MHz DDR4 RDIMM leads the rankings with this performance tier. Most other options operate at 2666MHz, 2400MHz, or 2133MHz. You must ensure your server motherboard supports 3200MHz to utilize this speed. Otherwise, the module will downclock to match the system limit.
Do all listed RDIMM modules support ECC?
Yes, every product in this guide includes ECC support. Registered DIMMs require Error Correction Code for server stability. This feature detects and corrects data corruption. Whether you choose a single 16GB stick or an 8-module kit, all options provide this essential error-checking capability for critical server workloads.
Which module offers the largest single capacity?
The Micron 64GB 3200MHz DDR4 RDIMM offers the largest single-module capacity at 64GB. This allows for maximum density per slot on compatible DDR4 platforms. While kits exist, this single stick provides the highest individual capacity. It is ideal for administrators needing to maximize memory in each available DIMM slot.
What is the standard operating voltage for these modules?
The standard operating voltage is 1.2V. Most listed modules, including those from SK Hynix, Crucial, and Samsung, specify 1.2V. This low voltage helps reduce power consumption and heat generation. You should verify that your server power delivery supports this standard voltage for stable operation.
Are there kits available for dual-channel configurations?
Yes, several kits are designed for dual-channel setups. The Crucial 64GB (2x32GB) 2666MHz kit and the Samsung 64GB (2x32GB) kit both provide balanced dual-channel performance. These kits include two matching modules to ensure synchronized operation. They are suitable for servers requiring balanced memory bandwidth across two channels.
Which option is best for legacy 2133MHz servers?
The SK Hynix 32GB DDR4-2133 RDIMM and the A-Tech 32GB DDR4-2133 ECC RDIMM are suitable for legacy systems. These modules run at 2133MHz, matching older server specifications. They provide reliable ECC performance without requiring higher-speed compatibility. Choose these if your motherboard only supports up to 2133MHz.