Samsung M321RAGA0B20-CWK
- Part Number: M321RAGA0B20-CWK
- Manufacturer: Samsung
- Capacity: 128GB
- Memory Type: DDR5
- Module Type: RDIMM
- Speed: 4800 MT/s
- Module Name: PC5-38400R
- Rank / Org: 4Rx4
- ECC: Yes
- Voltage: 1.1V
- Pins: 288-pin
This Samsung module is a 128GB DDR5-4800 registered DIMM (RDIMM), 4Rx4, with ECC. Samsung makes both the DRAM and the finished module. It uses 3DS stacking to reach 128GB at this rank configuration.
Use this page when the label shows this part number, or when you need 128GB DDR5-4800 RDIMM 4Rx4 for a server build or replacement.
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Technical Overview
Samsung M321RAGA0B20-CWK is a 128GB DDR5-4800 RDIMM with a 4Rx4 organization and ECC. The module name is PC5-38400R. Samsung builds both the DRAM and the finished server module. This part uses 3DS DRAM, so it is not the same ordering class as the later 128GB 2Rx4 modules at 5600 or 6400.
Most requests start from the number on the label, or from a build that needs 128GB DDR5-4800 RDIMM 4Rx4. Send the exact part number when you have it. If you only know the specification, send capacity, speed, module type and rank.
How to Read This Part Number
- M321R — Samsung DDR5 RDIMM family
- AGA0 — 128GB module density
- B20 — die and package revision (3DS)
- CWK — DDR5-4800 speed grade
Use the full code on the quote. Nearby AJA0 modules at 5600/6400 are typically 2Rx4. Those are different products.
Key Specifications
Part Number: M321RAGA0B20-CWK
Manufacturer: Samsung
Capacity: 128GB (1x 128GB)
Memory Type: DDR5 SDRAM
Module Type: RDIMM (Registered DIMM)
Speed: 4800 MT/s
Module Name: PC5-38400R
Rank / Organization: 4Rx4
Error Correction: ECC
Voltage: 1.1V
Pin Count: 288-pin
Form Factor: Standard-height DIMM
Before adding memory to a populated server, match these values against the modules already installed: capacity, DDR generation, RDIMM or LRDIMM, rank, organization, speed and voltage. Also confirm the platform supports 128GB 4Rx4 RDIMM.
RDIMM vs LRDIMM
This module is an RDIMM. Mixing RDIMM and LRDIMM in the same population is usually not allowed. If the installed memory is LRDIMM, quote an LRDIMM equivalent, or send a photo of the current label.
Where This Module Is Used
- Replacing the same Samsung DDR5 RDIMM already in the server
- Upgrades that specify 128GB DDR5-4800 RDIMM, 4Rx4
- Builds and spare stock that call out this exact code
The same Samsung module may also appear under an HPE, Dell, Cisco, Supermicro or Lenovo label. If you need the OEM-labeled stick, include that number on the quote as well.
Matching Related Modules
A different speed, rank, density, or RDIMM vs LRDIMM code is a different product. Before approving a substitute, match:
- 128GB
- DDR5-4800 / PC5-38400R
- RDIMM
- 4Rx4
- ECC
- 1.1V / 288-pin
Do not treat a 128GB 2Rx4 DDR5-5600/6400 module as a drop-in for this 4Rx4 DDR5-4800 part.
What to Send for a Quote
- Part number: M321RAGA0B20-CWK
- Quantity
- Optional: server brand and model
- Optional: photo of the module label
- Or: 128GB + DDR5-4800 + RDIMM + 4Rx4
Mixed lists are fine, including other DDR4/DDR5 lines and OEM-labeled pulled memory.
FAQ
Is this an LRDIMM?
No. It is a Samsung DDR5 RDIMM. Confirm the installed type before ordering.
Is this the same as M321RAJA0MB0-CWM?
No. That nearby 128GB code is typically DDR5-5600 2Rx4. This part is DDR5-4800 4Rx4. Quote the exact number on your label.
Can I order only a few pieces?
Yes. Orders can start at two modules.
Do you quote OEM-labeled versions too?
Yes. Include the HPE, Dell, Cisco, Supermicro or Lenovo number if the server needs that label.