Samsung M386A8K40BM2-CTD

M386A8K40BM2-CTD Technical Overview

Samsung M386A8K40BM2-CTD is a 64GB DDR4-2666 LRDIMM with a 4Rx4 organization and ECC. The module name is PC4-21300L. Samsung builds both the DRAM and the finished server module, so this ordering code identifies a complete factory part.

Most requests start from the number on the label, or from a build that needs 64GB DDR4-2666 LRDIMM 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

• M386A — Samsung DDR4 LRDIMM family
• 8K40 — 64GB density with x4 DRAM organization
• BM2 — die and package revision
• CTD — DDR4-2666 speed grade

Use the full code on the quote. Nearby suffixes can look similar on the sticker but are not always the same module.

Key Specifications

Part Number: M386A8K40BM2-CTD
Manufacturer: Samsung
Capacity: 64GB (1x 64GB)
Memory Type: DDR4 SDRAM
Module Type: LRDIMM (Load-Reduced DIMM)
Speed: 2666 MT/s
Module Name: PC4-21300L
Rank / Organization: 4Rx4
Error Correction: ECC
Voltage: 1.2V
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.

RDIMM vs LRDIMM

This module is an LRDIMM. Load-reduced parts are common when the server runs denser or higher-rank memory. Mixing LRDIMM and RDIMM in the same population is usually not allowed. If the installed memory is RDIMM, quote an RDIMM equivalent, or send a photo of the current label.

Where This Module Is Used

• Replacing the same Samsung LRDIMM already in the server
• Upgrades that specify 64GB DDR4-2666 LRDIMM, 4Rx4
• Refurbish 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, or RDIMM vs LRDIMM code is a different product. Before approving a substitute, match:

• 64GB
• DDR4-2666 / PC4-21300L
• LRDIMM
• 4Rx4
• ECC
• 1.2V / 288-pin

What to Send for a Quote

1. Part number: M386A8K40BM2-CTD
2. Quantity
3. Optional: server brand and model
4. Optional: photo of the module label
5. Or: 64GB + DDR4-2666 + LRDIMM + 4Rx4

Mixed lists are fine, including other DDR4/DDR5 lines and OEM-labeled pulled memory.

FAQ

Is this an RDIMM?
No. It is a Samsung DDR4 LRDIMM. Confirm the installed type before ordering.

Can I order only a few pieces?
Yes. Orders can start at two modules.

What if the label ending looks slightly different?
Send a photo of the full label. We will confirm whether it is the same family before quoting.

Do you quote OEM-labeled versions too?
Yes. Include the HPE, Dell, Cisco, Supermicro or Lenovo number if the server needs that label.