M321R4GA3BB0-CQKDG Samsung 32GB RAM RDIMM PC5-38400 Dual Rank DDR5 ECC 2RX8

Key Specifications

The transition to DDR5 technology marks a generational leap in memory performance and efficiency. The Samsung 32GB DDR5 module is built upon this new architecture, which fundamentally redesigns how data is handled between the memory and the processor.

On-Die ECC (Error Correction Code)

A cornerstone of DDR5 reliability. While the module also features traditional sideband ECC (more on that below), On-Die ECC operates within the memory chips themselves. It detects and corrects minor bit errors that can occur inside the DRAM chip before data is sent to the memory buffer. This proactive correction enhances data integrity at the source, reduces the corrective workload on the system-level ECC, and contributes significantly to overall system stability and chip longevity.

Decoding the Model: Samsung M321R4GA3BB0-CQKDG

This specific memory module belongs to a class of components designed for enterprise stability and long-term reliability. The alphanumeric string "M321R4GA3BB0-CQKDG" is not arbitrary; it is a detailed product code that reveals key specifications. Breaking it down, it indicates a 32GB capacity, DDR5 technology, ECC Registered design, and its performance grade. Such modules are typically sold and deployed in multiples to populate server banks, ensuring balanced channels and optimal performance for CPUs with multi-channel memory controllers, such as Intel Xeon Scalable processors (Sapphire Rapids, Emerald Rapids, and beyond) and AMD EPYC.

DDR5 Performance

This module operates at a data rate of 4800 Megatransfers per second (MT/s), commonly marketed as 4800Mbps. In terms of industry-standard naming, this equates to a PC5-38400 designation. The "PC5" refers to DDR5, and the "38400" represents the module's theoretical peak bandwidth in megabytes per second (MB/s). Calculating this involves multiplying the data rate (4800) by the bus width (64 bits = 8 bytes), which yields 38,400 MB/s of bandwidth per module. When populated across multiple channels in a modern server CPU, aggregate memory bandwidth can reach staggering levels, eliminating bottlenecks for data-heavy applications.

288-Pin RDImm

This Samsung module utilizes a 288-pin edge connector layout, which is physically and electrically incompatible with the 288-pin layout of DDR4 DIMMs. The pin assignments, voltages, and key notch positions are different. It is designed to fit into server motherboards with DDR5 RDIMM slots. The module is likely to feature a standard height and may incorporate a thermal sensor or support for PMIC (Power Management Integrated Circuit) management, though specifics depend on the exact product revision.

Dual 32-bit Sub-Channels

DDR5 memory modules feature a redesigned channel architecture. Each DIMM is divided into two independent 32-bit sub-channels (with ECC, this becomes 40-bit each). This doubling of channels compared to DDR4's single 64-bit channel allows for more efficient data handling, reducing latency and improving memory controller efficiency. For the server administrator, this translates to smoother handling of concurrent requests and better performance in multi-threaded, memory-sensitive applications.

Integrated Power Management IC (PMIC)

A critical advancement in DDR5. The PMIC is now located on the memory module itself, not the motherboard. This provides more stable and cleaner power delivery to the DRAM chips. For the Samsung M321R4GA3BB0-CQKDG, this means optimized voltage regulation for its 1.1V operation, improved power efficiency, and reduced signal noise—all contributing to higher data transfer reliability at high speeds and better support for future speed scaling.

Critical Specifications of the 32GB DDR5 RDIMM

Each specification is meticulously chosen to deliver optimal performance in targeted server platforms, primarily those based on the latest Intel Xeon Scalable (Sapphire Rapids, Emerald Rapids) and AMD EPYC (Genoa, Bergamo) processors.

Capacity: 32GB (1x32GB) 2Rx8

This module offers a substantial 32-gigabyte capacity as a single module. The "1x32GB" denotes a single module of 32GB capacity. The "2Rx8" configuration is a key detail: "2R" means the module is dual-rank. A rank is an independent set of DRAM chips that is accessed at one time. A dual-rank module effectively interleaves access between two sets of chips, improving performance by reducing latency between accesses. The "x8" refers to the organization of the individual DRAM chips—they have an 8-bit wide data interface. This organization is standard for high-capacity ECC modules and works in conjunction with the memory buffer to manage data flow and error correction.

Speed and Bandwidth: 4800 Mbps & PC5-38400

The module operates at a data rate of 4800 Megatransfers per second (MT/s), often referred to as 4800 Mbps. This is the speed at which data is clocked on the memory bus. The industry classification PC5-38400 derives from this: DDR5's 64-bit/8-byte data path multiplied by 4800 MT/s equals 38,400 MB/s of peak theoretical bandwidth per module (64 * 4800 / 8 = 38,400). This massive bandwidth is essential for feeding multi-core CPUs and alleviating data bottlenecks in server applications.

Power Efficiency: 1.1V Operation

DDR5 technology achieves higher performance at a lower operating voltage compared to DDR4 (typically 1.2V). The Samsung module runs at a standard voltage of 1.1V. This reduction directly lowers power consumption and heat generation within the server chassis. For large-scale deployments with hundreds or thousands of DIMMs, this voltage reduction translates into meaningful operational cost savings and a reduced cooling load and improved Power Usage Effectiveness (PUE) for the data center.

The Pillars of Server Memory: ECC and Registered Design

The "ECC Registered" portion of the module's description highlights its two most critical enterprise features, which distinguish it from unbuffered desktop memory.

ECC (Error Correcting Code) Memory

ECC is a non-optional feature for mission-critical systems. It provides hardware-level error correction to detect and correct the most common types of data corruption.

How ECC Protects Your Data

Extra memory bits are stored alongside the actual data bits (typically 8 extra bits for every 64 data bits, creating a 72-bit bus). A sophisticated algorithm checks the data as it is written and read. The ECC logic can detect single-bit and multi-bit errors and, crucially, automatically correct single-bit errors on the fly without any intervention from the operating system or application. This prevents silent data corruption, system crashes, and incorrect computational results that could be catastrophic in financial, scientific, or database environments.

Registered DIMMs (RDIMMs)

The "Registered" or "Buffered" aspect is equally important for server scalability and signal integrity.

The Role of the Register (RCD)

An RDIMM incorporates a register clock driver (RCD) chip on the module. This RCD acts as a buffer for the address and command signals from the server's memory controller. It reduces the electrical load on the controller by buffering these signals before they are sent to the individual DRAM chips. This allows a server motherboard to support a much larger number of memory modules per channel (often 2 or 3 DIMMs per channel) without degrading signal quality. This is essential for populating servers with large amounts of total memory (e.g., 1TB, 2TB, or more). The trade-off is a one-clock-cycle latency penalty, which is vastly outweighed by the gains in capacity and stability for enterprise use.

Physical and Operational Characteristics

The module's physical design ensures compatibility and reliable operation in server environments.

Form Factor

This Samsung module uses the standard 288-pin layout defined for DDR5 DIMMs. The pin count and key notch position are different from DDR4's 288-pin design (the notch is in a different location), preventing accidental insertion into an incompatible motherboard. The "RDIMM" specification ensures it has the necessary buffer chip and is keyed appropriately for server platforms that require registered memory.

SDRAM Type: Synchronous Dynamic RAM

SDRAM synchronizes all operations with the system clock, enabling precise timing and high-speed data transfers. The DDR5 (Double Data Rate 5) standard allows for two data transfers per clock cycle (one on the rising edge, one on the falling edge), effectively doubling the data rate compared to the clock speed.

Target Applications and Use Cases

The Samsung M321R4GA3BB0-CQKDG is not a general-purpose component; it is purpose-built for specific, demanding computing environments.

Enterprise Servers and Data Centers

This is the primary domain for this memory. It is designed for integration into rackmount and blade servers from major OEMs like Dell, HPE, Lenovo, and Cisco, as well as custom whitebox server builds.

In-Memory Databases

Platforms like SAP HANA, Oracle Database In-Memory, and Redis store actively queried data directly in RAM for ultra-low latency access. These systems demand both high capacity and the absolute data integrity provided by ECC RDIMMs to prevent database corruption.

High-Performance Computing (HPC) & Workstations

Technical workstations used for engineering simulation (CAD/CAE), scientific research, media rendering, and financial modeling benefit from the bandwidth and stability of server-grade memory. Platforms like Intel Xeon W or AMD Threadripper PRO that support ECC RDIMMs are ideal candidates for this module.