The HMA41GR7MFR4N-TF is an 8GB DDR4 Registered DIMM (RDIMM) manufactured by SK Hynix, engineered for high-reliability applications in server and workstation environments. Operating at a data rate of 2133 MT/s with a CAS Latency of 15, this module provides a balance of performance and stability. Its architecture incorporates a dual-rank, x4 organization and features on-board Error Correction Code (ECC) for enhanced data integrity, making it suitable for mission-critical computing tasks.
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What is the HMA41GR7MFR4N-TF?
The HMA41GR7MFR4N-TF is a high-density, high-performance 8GB (1Gx72-bit) DDR4 SDRAM Registered DIMM. The part number itself provides a detailed breakdown of its configuration: 'HMA' signifies an SK Hynix memory module, '4' indicates the use of 4Gb density DRAM components, '1G' denotes the total module capacity of 8GB (1 Giga-word), and 'R' specifies it as a Registered DIMM (RDIMM). The '7' in the part number indicates a 72-bit bus width, which is composed of a 64-bit data bus and an 8-bit bus for Error Correction Code (ECC) functionality. This ECC capability is critical for server environments, as it allows for the detection and correction of single-bit memory errors in real-time, preventing data corruption and system crashes.
Internally, the module is organized as a dual-rank (2R) configuration using DRAM components with a 4-bit data width (x4). This 2Rx4 architecture means the module contains two independent, 64-bit wide ranks of memory chips. The memory controller can access these ranks independently, which can improve performance through rank interleaving. The use of a Registering Clock Driver (RCD) is a defining characteristic of an RDIMM. The RCD acts as a buffer for the command, address, and clock signals between the memory controller and the DRAM chips. By buffering these signals, the RCD reduces the electrical load on the memory controller, enabling the system to support a larger number of memory modules and higher total memory capacity compared to unbuffered DIMMs (UDIMMs). This is essential for multi-socket server platforms that require substantial memory footprints. The 'TF' suffix designates the speed grade, corresponding to DDR4-2133P with primary timings of 15-15-15 (CL-tRCD-tRP) at a standard operating voltage of 1.2V. This module adheres to JEDEC standards for DDR4 memory, ensuring interoperability with compliant server platforms from major OEMs.
Pinout Configuration and Packaging
The HMA41GR7MFR4N-TF is packaged in a standard 288-pin DDR4 Dual In-Line Memory Module (DIMM) form factor. This JEDEC-compliant package has physical dimensions of approximately 133.35mm x 31.25mm. A key physical feature of the DDR4 DIMM is its curved edge connector, which helps reduce insertion force and ensures proper seating in the memory socket. The pinout is significantly different from its DDR3 predecessor, featuring a unique keying notch positioned to prevent accidental installation into incompatible motherboards.
The 288 pins are allocated to various signal groups critical for operation. These include:
- Data Bus (DQ0-DQ63): The primary 64-bit bidirectional path for data transfer.
- ECC Bus (CB0-CB7): An 8-bit bus dedicated to transferring ECC check bits, enabling error detection and correction.
- Address & Command Pins (A0-A17, BA0-BA1, BG0): Used by the memory controller to specify the memory location (row and column address, bank address, bank group) for read and write operations.
- Control Signals (RAS_n, CAS_n, WE_n, CS_n): These signals manage the command timing for activating rows, selecting columns, and initiating write operations.
- Clock Signals (CK_t, CK_c): A differential clock pair that synchronizes all operations on the memory module.
- Power and Ground (VDD, VSS, VPP, VREFCA, VREFDQ): Multiple pins are dedicated to providing the stable 1.2V (VDD) operating voltage, the 2.5V (VPP) word line boost voltage, and various reference voltages required for reliable signaling. The extensive use of power and ground pins is crucial for maintaining signal integrity and minimizing noise at high data rates.
The on-board RCD intercepts the address, command, and control signals from the motherboard before re-driving them to the DRAM chips, while the data (DQ) bus is connected directly between the system's memory controller and the DRAMs.
Core Architectural Features
- Registered Clock Driver (RCD): Features an on-board RCD chip that buffers address, command, and clock signals. This reduces the capacitive load on the memory controller, enabling greater memory scalability and signal integrity in systems with multiple DIMMs per channel.
- Full ECC Support: Implements a 72-bit wide bus (64 data + 8 ECC bits) to provide single-bit error correction and double-bit error detection (SEC-DED). This feature is non-negotiable for enterprise applications where data integrity is paramount.
- On-DIMM Thermal Sensor (TSOD): Integrates a JEDEC-compliant thermal sensor that allows the system's baseboard management controller (BMC) or BIOS to monitor the module's operating temperature. This enables closed-loop thermal control, preventing overheating and improving system reliability.
- Dual-Rank (2R) Architecture: Organized as two independent ranks of memory. This configuration allows for rank interleaving by the memory controller, which can hide memory latency and improve overall system bandwidth in certain workloads.
- Low Operating Voltage (1.2V): Operates at the standard DDR4 voltage of 1.2V, representing a significant power reduction compared to the 1.5V or 1.35V required by DDR3 modules. This contributes to lower overall power consumption and reduced heat generation in dense server environments.
Specifications Parameter Table
| Specification | Technical Details |
|---|---|
| Module Capacity | 8GB |
| Memory Technology | DDR4 SDRAM |
| Module Type | RDIMM (Registered Dual In-Line Memory Module) |
| Pin Count | 288-pin |
| Data Rate | 2133 MT/s (PC4-17000) |
| CAS Latency (CL) | 15 |
| Timing Parameters | 15-15-15 (CL-tRCD-tRP) |
| Operating Voltage (VDD) | 1.2V |
| Rank x Organization | 2Rx4 (Dual Rank, x4 bit organization) |
| Error Correction | ECC (Error Correction Code) |
HMA41GR7MFR4N-TF Equivalents, Cross Reference & Lifecycle
The HMA41GR7MFR4N-TF is an early-generation DDR4 module. While still functional for legacy systems, its 2133 MT/s speed places it in the "End of Life" (EOL) or "Not Recommended for New Designs" (NRND) lifecycle category. For maintenance and upgrades of existing compatible servers, it remains a viable component. When seeking alternatives, it is critical to match key parameters: capacity (8GB), type (DDR4 RDIMM), speed (PC4-17000 / 2133 MT/s), rank (2Rx4), and voltage (1.2V). A functionally similar equivalent from another major manufacturer is the Samsung M393A1G40DB0-CPB or the Micron MTA18ASF1G72PDZ-2G1. While these parts are often interchangeable, system integrators should always consult the server or motherboard's Qualified Vendor List (QVL) and perform validation testing to ensure full compatibility and stability before deployment. Minor differences in sub-timings or RCD behavior can sometimes lead to compatibility issues. For availability of this specific module for repairs or upgrades, you can Check HMA41GR7MFR4N-TF Inventory & Pricing.
Typical Applications & Circuit Considerations
The HMA41GR7MFR4N-TF is engineered specifically for enterprise-level computing platforms where stability, data integrity, and high memory capacity are primary design requirements. Its registered and ECC-enabled architecture makes it unsuitable for consumer desktops but ideal for a range of professional applications. These include entry-level to mid-range enterprise servers used for web hosting, database management, and application virtualization. It is also well-suited for high-performance workstations used in scientific computing, computer-aided design (CAD), financial modeling, and digital content creation, where calculation errors due to memory faults are unacceptable.
When integrating this module into a system design, several circuit-level considerations are critical. The Power Delivery Network (PDN) must supply a clean and stable 1.2V VDD rail with minimal voltage ripple, especially during high-current transient events like simultaneous switching of all data lines. This necessitates the use of high-quality, low-ESR bulk and decoupling capacitors placed physically close to the DIMM sockets on the motherboard. Signal integrity is paramount for reliable operation at 2133 MT/s. PCB traces for the data, address, and clock lines must be designed with controlled impedance, typically 40-50 ohms single-ended. The differential clock pairs (CK_t/CK_c) require precise intra-pair and inter-pair length matching to minimize timing skew. Furthermore, trace lengths from the CPU's integrated memory controller to each DIMM socket should be matched as closely as possible to ensure proper timing margins across the entire memory subsystem. DDR4 technology relies heavily on On-Die Termination (ODT) to manage signal reflections, and the motherboard BIOS must be configured correctly to select the appropriate ODT values based on the specific memory configuration. For engineers designing or upgrading systems requiring this level of reliability, it is beneficial to Browse DDR4 Series to understand the full range of available modules and their specifications.
Video Demonstration
Frequently Asked Questions (HMA41GR7MFR4N-TF FAQ)
Q: What is the primary difference between an RDIMM like the HMA41GR7MFR4N-TF and a standard UDIMM?
A: The key difference is the presence of a Registering Clock Driver (RCD) on the RDIMM. A UDIMM (Unbuffered DIMM) has a direct path for address and command signals from the memory controller to the DRAM chips. In contrast, an RDIMM like the HMA41GR7MFR4N-TF uses the RCD to buffer these signals, which reduces the electrical load on the memory controller. This allows a single memory channel to reliably support more memory modules and thus a higher total system memory capacity, which is essential for servers.
Q: Can I install the HMA41GR7MFR4N-TF in a typical consumer desktop computer?
A: It is highly unlikely to work. Most consumer desktop motherboards and processors are designed for Unbuffered DIMMs (UDIMMs) and lack the necessary BIOS and chipset support for Registered DIMMs. Furthermore, this module features ECC, which is also typically not supported by consumer-grade hardware. Attempting to install it will usually result in the system failing to POST (Power-On Self-Test).
Q: What does the '2Rx4' organization signify on this memory module?
A: The '2Rx4' designation describes the module's logical and physical architecture. '2R' stands for Dual Rank, meaning the module has two independent sets of DRAM chips that can be accessed by the memory controller. 'x4' indicates that each individual DRAM chip on the module has a 4-bit wide data bus. To create a 64-bit data bus for one rank, sixteen of these x4 chips are used, plus two additional chips for the 8-bit ECC bus.
Q: How does the Error Correction Code (ECC) function work on this module?
A: The HMA41GR7MFR4N-TF uses a 72-bit memory bus, comprising 64 bits for data and an extra 8 bits for the ECC code. When the system writes data to the memory, the memory controller calculates an 8-bit checksum (the ECC code) based on the 64 bits of data and stores it alongside the data. Upon reading the data back, the controller recalculates the checksum and compares it to the stored version, allowing it to detect and correct any single-bit errors that may have occurred due to electrical interference or other factors.
Q: What does the 'TF' speed grade in HMA41GR7MFR4N-TF indicate?
A: The 'TF' suffix is SK Hynix's designator for a specific speed and timing grade. For this module, 'TF' corresponds to a DDR4-2133P data rate, which means it can perform 2133 million transfers per second. It also specifies the primary JEDEC timing parameters as CL-tRCD-tRP of 15-15-15 at the standard 1.2V operating voltage. This information is critical for ensuring the module is compatible with the host system's memory controller settings.
Alan Carter
Senior Hardware Engineer & Component Specialist
Alan has over 15 years of expertise in embedded systems design, FPGA architecture, and global semiconductor supply chains. He specializes in component cross-referencing, lifecycle management, and helping OEMs navigate supply shortages.
