A9781930 Dell 64GB RAM 2666MHZ PC4-21300 Cl19 Ecc DDR4 SDRAM

General Information

• Brand Name: Dell
• Part Number: A9781930
• Product Type: 64GB DDR4 SDRAM Memory Module

Technical Specifications

• Storage Capacity: 64GB
• Memory Technology: DDR4 SDRAM
• Number of Modules: 1 x 64GB
• Bus Speed: 2666MHz DDR4-21300/PC4-2666V
• Data Integrity Check: ECC

Signal Processing and Latency

• Signal Processing: Registered
• CAS Latency Timings: CL19
• Rank Features: Quad Rank X4

Physical Characteristics

• Form Factor: 288-pin LRDIMM

Compatibility

• PowerEdge C6420
• PowerEdge FC640
• PowerEdge M640
• PowerEdge R440
• PowerEdge R540
• PowerEdge R640
• PowerEdge R740
• PowerEdge R740xd
• PowerEdge R940
• PowerEdge T440
• PowerEdge T640

Dell 64GB 2666MHz Memory Overview

The Dell A9781930 64GB 2666MHz PC4-21300 CL19 ECC Registered Quad Rank X4 1.2v Load-reduced DDR4 SDRAM 288-Pin LRDIMM for Server Memory Module defines a focused category of server memory tailored for enterprise-class workloads where capacity, reliability, and signal integrity matter. This category encompasses load-reduced dual in-line memory modules built for multi-socket servers, virtualization hosts, database appliances, and other mission-critical systems that demand dense memory configurations without compromising stability. LRDIMM technology redefines how memory population impacts system performance by using an onboard buffer to reduce electrical load on the memory controller, allowing servers to accept higher module counts and larger capacities compared to traditional RDIMM or UDIMM alternatives. The Dell A9781930 64GB 2666MHz PC4-21300 CL19 ECC Registered Quad Rank X4 1.2v Load-reduced DDR4 SDRAM 288-Pin LRDIMM for Server Memory Module category highlights modules that combine industry-standard 288-pin DDR4 form factors with load-reduced architecture, error-correcting code (ECC) reliability, registered signaling, quad rank organization, and X4 data width to meet the needs of enterprise data centers.

Technical characteristics

The primary defining attribute of modules in this category is the 64GB density. At 64 gigabytes per module, these LRDIMMs allow administrators to construct large total memory footprints using fewer sockets or fewer module slots. When planning for consolidated virtual machines, in-memory databases, or analytic workloads, the 64GB capacity becomes a tactical enabler for maximizing server utilization and reducing the number of physical servers.

Performance

The Dell A9781930 64GB 2666MHz PC4-21300 CL19 ECC Registered Quad Rank X4 1.2v Load-reduced DDR4 SDRAM 288-Pin LRDIMM for Server Memory Module category centers on a 2666MT/s speed grade, commonly expressed as DDR4-2666 or PC4-21300. This clock rate delivers an effective bandwidth that suits a broad range of server workloads, balancing latency and throughput. Architects selecting modules from this category value the PC4-21300 rating for its consistent, tested performance in mainstream server platforms. While modern systems sometimes offer higher DDR4 speeds, 2666MHz remains a pragmatic choice where compatibility, stability, and broad chipset support are essential.

Latency

Latency is an important metric for memory-sensitive applications. The CL19 timing indicates the column address strobe latency and is a commonly used timing for 2666MT/s modules. In this server memory category, CL19 provides an acceptable latency-to-bandwidth balance; when combined with load-reduced buffering and ECC, the result is a stable, predictable latency profile suited to database indexing, virtualization density, and steady-state compute tasks common in enterprise operations.

Voltage

For data center operators concerned about energy usage and heat dissipation, 1.2v DIMMs reduce per-module power consumption. Because energy costs scale with the number of DIMMs installed, choosing 1.2v LRDIMMs supports both sustainability goals and operational cost control without sacrificing reliability.

ECC

Error Correcting Code (ECC) and registered signaling are core features that distinguish server-grade memory from desktop memory. ECC automatically detects and corrects single-bit errors and flags multi-bit errors, offering resilience against transient faults and improving system uptime. Registered memory introduces a register between the memory controller and DRAM chips to stabilize signals, particularly when many modules are populated. Modules in the Dell A9781930 category combine ECC and registered features with load-reduced buffering to maximize error resilience and signal integrity for mission-critical servers.

Quad Rank

Quad rank indicates that the module contains four independent sets, or ranks, of memory chips that the controller can access separately. X4 data width identifies the internal organization where each DRAM chip contributes 4 bits of data to the data path. A quad rank X4 LRDIMM offers higher raw capacity while maintaining compatibility with server controllers that support multi-rank modules.

Compatibility

Memory compatibility is a pivotal concern when selecting modules in this category. The Dell A9781930 64GB 2666MHz PC4-21300 CL19 ECC Registered Quad Rank X4 1.2v Load-reduced DDR4 SDRAM 288-Pin LRDIMM for Server Memory Module category is engineered to match a wide variety of enterprise server boards and OEM systems that explicitly support LRDIMM modules. Because load-reduced memory places a buffer between the module and controller, it is essential to verify that the target server BIOS/UEFI and chipset microcode are updated to fully support LRDIMM behavior, especially when mixing ranks, capacities, or third-party modules.

Use Cases

Virtualization platforms benefit directly from the high-density characteristics of the Dell A9781930 64GB 2666MHz PC4-21300 CL19 ECC Registered Quad Rank X4 1.2v Load-reduced DDR4 SDRAM 288-Pin LRDIMM for Server Memory Module. When hosting many virtual machines on a single physical server, available RAM becomes the gating factor for consolidation and performance. Large 64GB LRDIMMs enable higher VM density per host, reduce the number of physical servers needed for a given workload, and simplify memory over commitment strategies when combined with memory management features in hypervisors.

Enterprise

Software-defined storage controllers, converged infrastructure appliances, and deduplication engines often allocate substantial memory for metadata, caching, and write buffering. Modules in the Dell A9781930 category provide the capacity and reliability required for storage controllers that serve many clients and drive high I/O throughput. Load-reduced DIMMs reduce signal integrity issues associated with many populated slots, enabling denser memory configurations in storage appliances.

Reliability

Memory modules under this category undergo rigorous validation procedures including burn-in tests, thermal cycling, error injection, and compatibility matrices across a wide range of server platforms. Validation ensures the Dell A9781930 64GB 2666MHz PC4-21300 CL19 ECC Registered Quad Rank X4 1.2v Load-reduced DDR4 SDRAM 288-Pin LRDIMM for Server Memory Module meets the reliability expectations of enterprise customers. Testing includes ECC function verification, rank switching, and signal integrity analysis to confirm that modules operate correctly at rated speeds and voltages under realistic workloads.

Comparisons

Choosing between LRDIMM, RDIMM, and UDIMM requires a clear understanding of workload and system priorities. LRDIMM modules like the Dell A9781930 series enable higher densities and more module population without overloading the memory controller, making them ideal for capacity-driven use cases. UDIMM, being unbuffered, is common in desktop or light server environments where maximum density is not required. Each topology has trade-offs in latency, cost, and maximum supported density, and the Dell A9781930 category positions itself where density and reliability are the dominant concerns.

DDR4-2666

Higher DDR4 speed grades can offer incremental bandwidth gains but may reduce compatibility and increase costs. Conversely, lower speeds might improve compatibility but sacrifice throughput. The Dell A9781930 2666MHz rating represents a pragmatic balance between performance and broad platform support. For many enterprise workloads, the throughput provided by PC4-21300 is sufficient, and the gains from higher-speed modules do not offset the potential compatibility or stability risks, particularly in large multi-DIMM configurations.