P73446-K21 HPE 256GB DDR5-6400MHz PC5-51200 ECC Registered RDIMM Memory

HPE P73446-K21 256GB DDR5 Smart Memory — Product 

The HPE P73446-K21 is a high-capacity, enterprise-grade 256GB DDR5 Smart Memory module (1×256GB) engineered for modern servers and mission-critical systems. Built to deliver ultra-fast data throughput, industry-leading reliability and advanced error protection, this registered ECC memory module is ideal for data centers, virtualization hosts and memory-intensive workloads that require both scale and stability.

Key Selling Points

• High capacity: single 256GB module for maximum density with minimal DIMM slots used.
• Blazing bandwidth: DDR5-6400 MT/s (PC5-51200) for faster data movement and lower latency in parallel workloads.
• Enterprise reliability: ECC with Registered 3DS signaling and Smart Memory features for robust data integrity.
• Energy-efficient: optimized at 1.1V for improved power profile compared to legacy memory standards.
• Optimized timings: CL60 tuned for stability at high-speed operation.

Technical Specifications & Detailed Attributes

Product Identification

• Manufacturer: HPE
• Part Number: P73446-K21
• Model Name: 256GB DDR5 Smart Memory Kit

Memory & Performance Characteristics

• Storage Capacity: 256GB (single module — 1 × 256GB)
• Memory Type / Technology: DDR5 SDRAM
• Speed / Bandwidth: 6400 MT/s (DDR5-6400) — PC5-51200
• CAS Latency: CL60 (optimized for DDR5-6400 operation)
• Voltage: 1.1 V (low-voltage operation for power efficiency)
• Memory Rank / Organization: Quad-rank, x4 device organization
• Error Handling: ECC (Error-Correcting Code) for data integrity
• Registration: Registered (RDIMM) with 3DS support
• Form Factor: 288-pin DDR5 DIMM

Compatibility & Use Cases

Common Server Workloads

• Virtualization and hypervisor hosts (large VM densities)
• In-memory caching and real-time analytics
• High-performance databases and OLTP/OLAP systems
• AI/ML training nodes and inference servers that benefit from big memory footprints
• Enterprise file servers and virtualization-backed storage appliances

Platform Considerations

Designed for HPE server platforms that explicitly support DDR5 registered ECC memory and quad-rank modules. Always verify motherboard/BIOS compatibility and supported memory population rules in your server's technical documentation. Mixing ranks, voltages or speeds can lead to suboptimal performance or non-boot situations — follow vendor-qualified memory lists when possible.

Best Practices for Deployment

• Install identical modules in matched channels for optimal dual/quad-channel performance.
• Update server firmware (BIOS/UEFI) to the latest vendor release before deploying new DDR5 modules.
• Use HPE-qualified part numbers for warranty and support continuity.
• When scaling memory, consider thermal and airflow implications in high-density racks.

Quad-Rank x4 DDR5-6400 memory for enterprise servers

Quad-rank DDR5 modules like the P73446-K21 deliver a compelling blend of capacity and parallelism. By stacking multiple DRAM devices and presenting multiple ranks, these modules increase the total number of addressable banks and open opportunities for higher sustained bandwidth under heavy concurrency. For memory-intensive tasks — large virtual machines, in-memory databases, analytics, and virtualization host consolidation — a single 256GB module reduces the number of DIMM slots required to achieve large total capacities, simplifying BOMs and enabling denser memory configurations per CPU socket.

Performance characteristics and platform advantages

At DDR5-6400 (PC5-51200) the module targets peak transfer rates suitable for modern CPU architectures that expose higher memory channels and improved prefetch efficiency. The CL60 timing reflects the tradeoff between absolute latency and high raw throughput common in very fast DDR5 modules; in real workloads, the throughput uplift often outweighs the higher CAS value by reducing stalls on large sequential transfers and multi-threaded memory access patterns.

Smart Memory and server optimization

HPE’s Smart Memory ecosystem pairs validated memory kits with firmware and server platform tuning. P73446-K21 is sold and supported as part of HPE’s DDR5 Smart Memory portfolio, which includes platform firmware hooks for thermal management, DIMM health telemetry, and server-level tuning to extract reliable bandwidth under real-world loads. Using vendor-validated memory reduces incompatibility risk and eases large-scale deployments where consistency and predictive maintenance matter.

Compatibility, supported platforms and part numbers

P73446-K21 is an HPE part number within a broader family of DDR5 Smart Memory kits. HPE publishes compatibility lists and QuickSpecs that indicate which ProLiant and HPE server generations support specific memory SKUs, required BIOS/firmware levels, and any population rules (e.g., maximum modules per channel, supported mixed-rank configurations). Always confirm compatibility against your exact server model and firmware level to ensure proper operation and performance. 

Population rules and practical guidance

• Follow the server vendor’s DIMM population rules — mixing ranks (single, dual, quad) across channels can change achievable speed and channel interleaving.
• Large quad-rank DIMMs can reduce the maximum number of modules a controller will run at full speed; plan capacity vs. speed tradeoffs.
• When building balanced systems, populate memory symmetrically across channels to maximize interleaving and latency hiding.

Comparisons and buying considerations

When selecting memory for a server deployment, consider the following axes: capacity per DIMM, DIMM count and slot availability, targeted memory speed, controller capability, price per GB, and vendor warranty/support. Quad-rank 256GB modules maximize per-DIMM capacity but typically cost more per module than smaller DIMMs; however, when calculating price per usable GB in a populated system, higher-density DIMMs can reduce total system cost by requiring fewer DIMM sockets and simplifying BOMs.

DDR5-6400 vs DDR5-5600 and lower speeds

DDR5-6400 modules like the P73446-K21 offer higher theoretical bandwidth than DDR5-5600 or DDR4 alternatives. Real world benefit depends on workload memory-boundness and system memory controller behavior. In many server applications that stream large amounts of data or have heavily parallelized memory access, the higher frequency noticeably improves throughput; in tightly latency-sensitive small-transaction workloads, the raw CAS latency differences may moderate the gains.