815100-B21: HPE 32GB (1x32GB) Dual Rank x4 DDR4-2666 CAS-19-19-19 Registered Smart Memory Kit

Also listed as: 815100-001, 840758-091, 815100-H21, 815100-K21, M393A4K40BB2-CTD · made by Samsung

The HPE 815100-B21 is a 32GB dual-rank registered ECC DDR4 memory module running at 2666 MT/s with CL19 timings at 1.2V. Designed as the bedrock enterprise memory configuration for HPE ProLiant Gen10 servers with 1st and 2nd Gen Intel Xeon Scalable or AMD EPYC 7002 series processors, it features authentic HPE SmartMemory EEPROM validation. When purchasing second-hand DIMMs, inspect gold contact fingers for scratching, verify SPD authenticity in iLO, and check for counterfeit relabels.

Specifications

About the 815100-B21

815100-B21 is HPE's workhorse 32GB dual-rank (2Rx4) DDR4-2666 Registered SmartMemory kit (CL19-19-19) operating at 1.2V. Engineered specifically for the launch generation of HPE ProLiant Gen10 servers powered by 1st Generation Intel Xeon Scalable (Skylake-SP) and early 2nd Gen Xeon Scalable processors, it was the highest-volume memory SKU in enterprise data center deployments. It delivers registered ECC reliability, low thermal output, and authentic HPE SmartMemory qualification, unlocking specialized memory error recovery algorithms in HPE Active Health System.

Compatibility

This 288-pin RDIMM is compatible across all HPE ProLiant Gen10 platforms including the DL360 Gen10, DL380 Gen10, DL560 Gen10, DL580 Gen10, and ML350 Gen10. It also operates in Gen9 servers (such as DL380 Gen9), where it downclocks to 2400 MT/s or 2133 MT/s depending on processor capabilities. While it can physically install alongside DDR4-2933 modules in Gen10 systems, all channels will downclock to 2666 MT/s. It cannot be mixed with Load-Reduced DIMMs (LRDIMMs) or unbuffered ECC modules. The option code is 815100-B21, with spare numbers 815100-001 and 840758-091.

How to identify a genuine unit

A genuine 815100-B21 module bears an authentic HPE holographic security label alongside the OEM memory label from Samsung (typically model M393A4K40BB2-CTD), Micron, or SK hynix. Inside iLO 5, the module is authenticated as genuine HPE SmartMemory with authentic serial number tracking and complete SPD data. Relabelled generic DIMMs lacking authentic HPE SPD signatures will show as third-party non-authenticated memory in iLO, potentially triggering non-optimal memory performance notifications.

Buying used

Because 32GB DDR4-2666 RDIMMs are among the most commonly traded memory modules on the secondary market, buyers should carefully inspect physical condition. Verify that all 288 gold contacts are clean and free of abrasive scratches or solder burns. Request that sellers provide diagnostic verification from HPE Smart Storage Administrator or MemTest86+ showing zero single-bit or multi-bit errors. Ensure modules ordered in pairs share identical rank configurations (2Rx4) to maintain symmetric channel interleaving.

Reference prices (last 12 months, updated 2026-10-27)

Prices seen on public listings on the dates shown, before tax and shipping. Not an offer.

Fits these models

• HPE ProLiant DL380 Gen10
• HPE ProLiant DL360 Gen10
• HPE ProLiant DL385 Gen10 Plus v2
• HPE ProLiant DL325 Gen10 Plus v2
• HPE ProLiant DL560 Gen10
• HPE ProLiant DL580 Gen10
• HPE ProLiant ML350 Gen10

Equivalent part numbers

• Samsung M393A4K40BB2-CTD Samsung OEM 32GB 2Rx4 PC4-2666V RDIMM bare module

FAQ

Sources

• HPE DDR4 SmartMemory 32GB 2666MHz Kit, checked 2026-10-27