M393A8G40CB4-CWECQ Samsung 64GB RDIMM PC4-25600 Memory Module

Overview of the Samsung 64GB DDR4 Memory Module

The Samsung M393A8G40CB4-CWECQ 64GB DDR4 memory module is a high-performance server-grade component designed to enhance the capabilities of enterprise systems. This single module offers reliable, fast, and efficient memory, ideal for handling demanding workloads in server environments. Packed with robust features like ECC (Error Correction Code) for data integrity, it ensures smooth and stable performance for business-critical applications.

Understanding of 64GB Server Memory Kit

In the realm of enterprise computing and data center operations, system memory is not merely a performance component; it is a cornerstone of stability, reliability, and data integrity. The Samsung M393A8G40CB4-CWECQ represents a specific class of memory engineered explicitly for these demanding environments. This 64GB DDR4 module is not a standard desktop DIMM but a sophisticated server-grade component designed for systems where uninterrupted operation and error-free data processing are non-negotiable. Its technical specifications—from its ECC Registered architecture to its specific timing and voltage—tell the story of a product built for multi-socket servers, high-density virtualization hosts, and mission-critical database applications.

Key Specifications

At its core, the Samsung M393A8G40CB4-CWECQ is defined by a precise set of parameters that dictate its compatibility and performance envelope. Understanding each element of its part number and specification is crucial for proper system integration.

Decoding the Part Number: M393A8G40CB4-CWECQ

Samsung's part numbering system provides a wealth of information. The "M393" prefix typically indicates a registered ECC RDIMM for server use. "A8" denotes 8Gb-based DDR4 components. "G40" specifies the organization and bit width, here indicating a 64-bit data path with 4 internal banks per chip. The "CB4" segment often refers to the module's revision and design. Finally, the suffix "CWECQ" is a critical compatibility code: "C" for 1.2V operation voltage, "W" for the specific speed grade (3200 Mbps), "E" for ECC, "C" for registered (RDIMM), and "Q" for the thermal sensor profile (TSV2). This alphanumeric string is the definitive key to ensuring you are procuring the exact module required for your server platform.

Memory Capacity: 64GB (1x64GB) 2Rx4

This module offers a substantial 64-gigabyte capacity as a single physical unit. The configuration "2Rx4" is a vital detail. "2R" means the module is dual-rank, indicating the memory chips are organized into two independent sets (ranks) that the memory controller can access alternately, improving efficiency over a single-rank (1R) design. The "x4" refers to the data width of the individual DRAM chips; x4 chips are essential for supporting advanced error correction and are standard on high-capacity registered modules. This 2Rx4 architecture using 8Gb components is a classic and reliable design for achieving high-density memory in servers.

Performance Parameters: Speed, Timing, and Voltage

The module's performance is quantified by three interlinked specifications: speed, latency, and power.

Operating Speed: 3200 Mbps & PC4-25600

The module operates at a data rate of 3200 Megatransfers per second (MT/s), commonly referred to as 3200 Mbps. This is also expressed as "PC4-25600." The PC4 designation confirms it is a DDR4 module. The number 25600 represents the peak theoretical transfer bandwidth in megabytes per second (MB/s) for the module. It is calculated as (3200 MT/s * 8 bytes per transfer) = 25,600 MB/s. This high bandwidth is crucial for feeding data-hungry multi-core CPUs and reducing bottlenecks in data-intensive applications.

Latency: CAS Latency CL22

The CAS Latency (CL22) is the number of clock cycles between the memory controller issuing a read command and the first piece of data being available. At 3200 MT/s, a CL22 timing is a standard and balanced latency for server-grade ECC RDIMMs. Server memory prioritizes stability and compatibility over ultra-tight timings, and this CL22 rating ensures reliable operation across a wide range of server motherboards and under sustained loads.

Power Efficiency

The module operates at the standard DDR4 voltage of 1.2 volts. This represents a significant power efficiency improvement over older DDR3 (1.5V) technology, reducing the power consumption and heat generation of the memory subsystem—a critical factor in densely populated server racks where energy costs and thermal management are paramount.

Advanced Server Memory Technologies

What truly distinguishes this module from consumer memory are the embedded technologies for enhanced reliability and system scalability.

Error Correction Code (ECC) Functionality

ECC is a non-negotiable feature for enterprise servers. It enables the memory module to detect and correct the most common types of internal data corruption (single-bit errors) and detect multi-bit errors. This happens in real-time, transparent to the operating system and applications, preventing silent data corruption that could lead to crashed applications, corrupted databases, or incorrect scientific calculations. The Samsung M393A8G40CB4-CWECQ includes dedicated ECC chips alongside the data chips to provide this essential protection.

Registered (Buffered) Architecture: RDIMM

This is a Registered Dual In-Line Memory Module (RDIMM). It incorporates a register (or buffer) on the module itself, located between the memory controller and the DRAM chips. This register buffers the command, address, and control signals, reducing the electrical load on the memory controller. This allows a server system to support a much greater number of memory modules (and thus, higher total capacity) per CPU channel while maintaining signal integrity. The trade-off is a tiny, fixed latency penalty (typically one clock cycle) that is inconsequential for server workloads compared to the benefit of massive, stable memory expansion.

Comparison with Unbuffered (UDIMM) and Load-Reduced (LRDIMM) Modules

It is important to contrast this RDIMM with other types. Unbuffered DIMMs (UDIMMs), common in desktops, lack a register and place a direct electrical load on the controller, limiting how many can be installed. Load-Reduced DIMMs (LRDIMMs) use a more advanced buffer (iSO) that buffers the data signals as well, enabling even higher capacities and densities than RDIMMs but at a higher cost and sometimes slightly higher latency. The Samsung M393A8G40CB4-CWECQ RDIMM sits in the optimal middle ground, offering high capacity (64GB), excellent stability, and widespread compatibility in mainstream multi-socket servers.

Physical Form Factor: 288-Pin RDIMM

The module adheres to the standard DDR4 RDIMM physical design with 288 electrical contacts. The key notch is in a different position compared to DDR3, preventing accidental insertion into an incompatible slot. The RDIMM form factor is mechanically keyed to ensure it can only be installed in servers designed to support registered memory.

Primary Applications and Use Cases

The specific attributes of this memory module make it ideal for several key enterprise and data center scenarios.

Enterprise Servers and Virtualization Hosts

This is the primary application. Servers from vendors like Dell (PowerEdge), HPE (Proliant), Lenovo (ThinkSystem), and Cisco (UCS) that utilize Intel Xeon Scalable or AMD EPYC processors commonly use 3200 MT/s DDR4 RDIMMs. A 64GB module like this allows for building virtualization hosts with very high RAM counts (e.g., populating a 2-socket server with 16 slots to achieve 1TB of RAM), enabling the consolidation of dozens or hundreds of virtual machines on a single physical host.

Database and In-Memory Processing

Relational databases (SQL Server, Oracle), NoSQL databases, and in-memory data platforms (SAP HANA, Redis) thrive on large, fast, and reliable memory pools. The 64GB capacity per module allows databases to cache immense datasets in RAM, dramatically accelerating query times and transaction throughput. The ECC protection is especially critical here to safeguard the integrity of the core business data held in memory.

High-Performance Computing (HPC)

In computational workloads such as scientific simulations, financial modeling, and 3D rendering, large datasets must be held in memory for processors to work on efficiently. The high bandwidth (PC4-25600) of this module helps feed these calculations, while ECC ensures the accuracy of the computed results, which is fundamental in research and engineering contexts.

Compatibility and System Integration

Proper integration requires attention to detail beyond just the specifications listed.

Platform and CPU Generation Support

This 3200 MT/s DDR4 RDIMM is compatible with server platforms designed for DDR4 memory, typically those featuring Intel's 2nd/3rd/4th Gen Xeon Scalable processors (Cascade Lake, Ice Lake, Sapphire Rapids) and AMD's 2nd/3rd Gen EPYC processors (Rome, Milan). It is imperative to consult the server manufacturer's memory qualification list to confirm that this exact Samsung part number (M393A8G40CB4-CWECQ) is validated for a specific server model and configuration. Mixing memory modules of different speeds, timings, or capacities can sometimes force the system to run all memory at the lowest common denominator.

Memory Channels for Optimal Performance

Server CPUs have multiple memory channels (typically 6, 8, or 12). For optimal performance, modules should be installed in a balanced fashion across all channels. Most servers require memory to be installed in pairs or sets of four per CPU. When using 64GB RDIMMs, planning the configuration to leverage multi-channel bandwidth is key to unlocking the full potential of both the memory and the CPU.