What Is the Samsung M393AAK40B42-CWD 128GB DDR4-2666 LRDIMM?

The Samsung M393AAK40B42-CWD is a genuine 128GB DDR4 server memory module. It runs at 2666MHz. It follows the PC4-21300 standard. It uses ECC Load Reduced design. The layout is octal-rank, x4. It uses a 288-pin form factor at 1.2V.

Octal-rank LRDIMM packs eight ranks onto one module. It uses a data buffer chip. This was one of the earliest ways to reach 128GB per module. Newer 3DS die-stacking came later. The module carries a CL19 latency rating.

Samsung M393AAK40B42-CWD Specifications

• Brand: Samsung
• Part Number: M393AAK40B42-CWD
• Capacity: 128GB
• Speed: 2666MHz (PC4-21300)
• Memory Type: DDR4 ECC Load Reduced (LRDIMM)
• CAS Latency: CL19
• Rank and Width: Octal-Rank, x4
• Voltage: 1.2V
• Pin Count: 288
• Form Factor: Standard Height LRDIMM
• Condition: Refurbished, tested, and verified functional

Which Servers Use This Module?

This module fits enterprise servers built for high-density DDR4-2666 memory. Many Dell, HP, and Lenovo models support octal-rank LRDIMM. Always check your exact model's memory list first. Octal-rank support is less common than quad-rank.

Is This Module New or Refurbished?

This module is refurbished, not new. Each one is cleaned and tested. This confirms it works before it gets listed. The chips are genuine Samsung dies. A 30-day warranty covers every order.

Best Uses for This Memory Module

This module suits an older server with top density needs. Large in-memory databases and busy hosts benefit most. It also replaces a failed octal-rank module with a matched part.

Common Questions

Is octal-rank memory harder to find than quad-rank?

Yes. Fewer platforms support octal-rank. Check your server's memory documentation before ordering a replacement.

Does octal-rank memory run slower than quad-rank at the same speed?

No. Rank count affects addressing and density, not speed. Both run at the rated MHz if the platform supports it.