Samsung 128GB DDR5-5600 ECC Registered RDIMM 2Rx4 (M321RAJA0MB2-CWM)

Reasons to choose this module

• 128GB in one standard RDIMM slot for large virtualisation, database and AI host-memory configurations.
• Registered design buffers clock, command and control signals for dense memory populations.
• Error correction via 8 additional ECC bits per subchannel.
• Dual rank 2Rx4 organisation at 1.1V.

Platform compatibility checklist

• Confirm the CPU and motherboard support registered DDR5 (RDIMM). Desktop UDIMM-only boards will not run it.
• Do not mix RDIMMs with UDIMMs, or with 3DS/LRDIMM/MRDIMM modules, in one system.
• Check the server vendor qualified memory list for this exact part number and the required BIOS level.
• Follow the DIMMs-per-channel population rules; speed may drop below 5600 MT/s with two DIMMs per channel.
• Match capacity, rank and speed across all modules in a channel set for balanced memory population.
• Confirm the platform supports 128GB RDIMMs and the resulting total memory capacity.

Technical specifications

In the box

1 × Samsung 128GB DDR5-5600 ECC RDIMM, M321RAJA0MB2-CWM.

Single memory module, typically supplied in bulk/ESD packaging. No heat spreader, CPU, motherboard or system is included.

Dispatch, packaging and warranty

Dispatch within 24–48 hours (business days). Stock shown on the page is not a reservation, and transit time to your address is separate from dispatch.

Estimated protective shipping parcel: 25 × 15 × 6 cm, 0.3 kg total. These are packing estimates, not product dimensions; final packed size and weight may vary.

Manufacturer warranty under Samsung terms for server memory modules. Proof of purchase and manufacturer terms apply; contact us to start a claim. Statutory consumer rights remain unaffected.

Frequently asked questions

Will this RDIMM work in a normal DDR5 desktop motherboard?

No. Consumer DDR5 boards take unbuffered UDIMMs only. This module needs a platform that explicitly supports registered DDR5 RDIMMs.

Is this one module or a kit?

You receive one 128GB module. Order the number of modules your channel population requires; it is not a matched multi-module kit.

Will it always run at 5600 MT/s?

It is rated DDR5-5600. The CPU, BIOS and DIMMs-per-channel population decide the actual speed, which may be lower with 2DPC.

Does my server support 128GB modules?

Check the server or motherboard memory support list for 128GB DDR5 RDIMMs and the maximum total capacity per CPU before ordering.

Does DDR5 on-die ECC make any module equivalent to this one?

No. This RDIMM has full side-band ECC plus a register. On-die ECC in desktop DDR5 is a different, internal feature.

Can this RAM add to the VRAM of my graphics card?

No. System memory and GPU memory are separate resources. Plan host memory and GPU VRAM independently around the models and software you intend to run.

Manufacturer reference

Samsung Semiconductor DDR5 RDIMM product family