In the data center, RAM is the fuel that powers virtualization. As virtual machines (VMs) get larger and databases grow more complex, the old standard of 16GB or 32GB sticks just doesn't cut it anymore.
Enter the Samsung M393A8G40AB2-CWEBY.
This 64GB DDR4-3200 RDIMM has become the industry standard for high-density server deployments. Whether you are upgrading a Dell PowerEdge or building a new HPE ProLiant cluster, this specific part number is likely on your Bill of Materials.
But with server memory, the details matter. What does "2Rx4" mean for performance? Can you mix it with your existing RAM? This guide breaks down the specs.
Table of Contents
- 1. Decoding the Part Number
- 2. Technical Specs: The Power of 2Rx4
- 3. Compatibility Guide (Dell, HPE, Lenovo)
- 4. RDIMM vs. LRDIMM: A Critical Warning
- 5. Conclusion
1. Decoding the Part Number
Samsung memory part numbers are like a secret code. Here is how to read M393A8G40AB2-CWE:
| Code Segment | Meaning | Detail |
|---|---|---|
| M393 | Type | RDIMM (Registered DIMM) with ECC. |
| A | Generation | DDR4. |
| 8G | Density | 8Gb dies. High density allows for 64GB capacity on a single stick. |
| 40 | Org | x4 Organization. Optimized for server ECC and Chipkill redundancy. |
| AB2 | Revision | Rev B. A mature silicon revision known for stability. |
| CWE | Speed | 3200 Mbps (PC4-3200AA). The "AA" denotes CL22 latency. |
2. Technical Specs: The Power of 2Rx4
The most important spec on this stick—aside from the 64GB capacity—is its Rank Organization: 2Rx4 (Dual Rank).
Why Dual Rank?
- Performance: Dual Rank memory allows the memory controller to perform "Rank Interleaving." While one rank is refreshing or resetting, the controller can access the other rank. This typically results in 5-10% better performance compared to Single Rank memory in real-world workloads.
- Capacity vs. Load: While Quad Rank (4R) LRDIMMs exist for massive capacities (like 128GB), they often force the memory bus to slow down (clock down) to maintain signal integrity. The 2Rx4 configuration of the M393A8G40AB2-CWEBY hits the "sweet spot"—offering high capacity (64GB) while usually running at full 3200 MT/s speed.
Key Specifications
- Capacity: 64GB
- Speed: DDR4-3200 (PC4-25600)
- Voltage: 1.2V (Standard Low Voltage)
- ECC: Yes (Registered / Buffered)
- Latency: CL22 (22-22-22)
3. Compatibility Guide (Dell, HPE, Lenovo)
This Samsung module is the OEM basis for many "branded" memory sticks sold by server manufacturers. It is widely compatible with:
- Dell PowerEdge: Gen 14 (R740, R640, T640) and Gen 15 (R750, R650).
- Note: For Gen 14 servers, you need 2nd Gen Xeon Scalable (Cascade Lake) CPUs to reach full 2933/3200 speeds.
- HPE ProLiant: Gen 10 and Gen 10 Plus (DL380, DL360).
- Lenovo ThinkSystem: SR650, SR630.
Pro Tip: You do not always need to buy the expensive "System Branded" RAM. The M393A8G40AB2-CWEBY is often the exact same hardware found inside the Dell/HPE plastic packaging, just without the markup.
4. RDIMM vs. LRDIMM: A Critical Warning
This is the #1 mistake buyers make.
- M393... indicates this is an RDIMM (Registered DIMM).
- M386... would indicate an LRDIMM (Load Reduced DIMM).
You cannot mix them. If your server already has 128GB LRDIMMs installed, you cannot add this 64GB RDIMM. The server will halt at POST with a memory configuration error. Always match the type!
When to choose this RDIMM? Choose this RDIMM for almost all standard deployments. Only switch to LRDIMM if you plan to exceed 1.5TB or 2TB of RAM per CPU socket.
5. Conclusion
The Samsung M393A8G40AB2-CWEBY is the workhorse of the modern cloud. It offers the perfect balance of density, speed, and reliability. For expanding virtualization clusters or boosting SQL database performance, swapping out small 16GB sticks for these 64GB giants is the most cost-effective upgrade you can make.
Sourcing Genuine Samsung Server Memory Counterfeit RAM is a real risk in the supply chain. Ensure you are buying verified, original Samsung modules. Visit Aichiplink.com to check stock and pricing for the M393A8G40AB2-CWEBY.
Written by Jack Elliott from AIChipLink.
AIChipLink, one of the fastest-growing global independent electronic components distributors in the world, offers millions of products from thousands of manufacturers, and many of our in-stock parts is available to ship same day.
We mainly source and distribute integrated circuit (IC) products of brands such as Broadcom, Microchip, Texas Instruments, Infineon, NXP, Analog Devices, Qualcomm, Intel, etc., which are widely used in communication & network, telecom, industrial control, new energy and automotive electronics.
Empowered by AI, Linked to the Future. Get started on AIChipLink.com and submit your RFQ online today!
Frequently Asked Questions
1. What is the Samsung M393A8G40AB2-CWEBY?
It is a 64GB DDR4-3200 ECC RDIMM designed for enterprise and data center servers.
2. What does 2Rx4 mean in server memory?
2Rx4 means dual-rank, x4 organization, offering better performance and stronger ECC reliability than x8 modules.
3. Is this RAM compatible with Dell and HPE servers?
Yes. It is widely compatible with Dell PowerEdge, HPE ProLiant, and Lenovo ThinkSystem servers.
4. Can this RDIMM be mixed with LRDIMM memory?
No. RDIMM and LRDIMM cannot be mixed in the same server system.
5. Why is this module popular for virtualization?
Its 64GB capacity, ECC support, and dual-rank design make it ideal for virtual machines and database workloads.
