HPE 16GB DDR4-2666 ECC Registered DIMM — 840756-091

The HPE 840756-091 is a 16GB DDR4-2666 (PC4-21300) ECC Registered DIMM in a dual-rank 2Rx8 configuration for HPE ProLiant Gen10 servers. Operating at 1.2V with CL19 latency, the 2Rx8 layout uses x8 DRAM devices — offering a different electrical profile from 2Rx4 modules at the same capacity — and carries an HPE factory/OEM configuration suffix.

Key Features

• 16GB DDR4-2666 RDIMM factory variant — 2Rx8 configuration for Gen10 ProLiant platforms
• 2666MHz (PC4-21300) for Intel Xeon Scalable 1st/2nd Gen server memory bandwidth
• Dual-rank 2Rx8 architecture using x8-wide DRAM devices for cost-effective 16GB density
• 1.2V ECC registered operation for reliable multi-DIMM server configurations

Product Specifications

• Part Number: 840756-091
• Manufacturer: HPE
• Capacity: 16GB
• Type: DDR4 ECC Registered (RDIMM)
• Speed: 2666MHz (PC4-21300)
• CAS Latency: CL19
• Voltage: 1.2V
• Ranks x Width: 2Rx8
• Pins: 288-pin

Memory Specifications

• Memory Standard: JEDEC DDR4-2666
• Error Correction: ECC (Error Correcting Code)
• Buffer Type: Registered (RDIMM)
• DRAM Generation: DDR4

Performance Specifications

• Peak Bandwidth: ~42.7 GB/s (PC4-21300)
• ECC Type: Single-bit error correction, multi-bit error detection
• RAS Features: Advanced ECC, rank sparing, memory mirroring (platform dependent)

Use Cases

• HPE ProLiant Gen10 factory-configured 16GB DDR4-2666 memory replacement
• Entry-level and mid-range Gen10 server deployments requiring 16GB per slot
• Virtualization and general-purpose application servers on Xeon Scalable Gen10
• Mixed-capacity memory builds alongside 32GB modules in supported Gen10 configurations

Compatibility

• HPE ProLiant DL380 Gen10, DL360 Gen10, DL180 Gen10
• HPE ProLiant ML350 Gen10, BL460c Gen10
• Intel Xeon Scalable 1st/2nd Generation (Skylake-SP / Cascade Lake-SP) supporting DDR4-2666

Frequently Asked Questions

What is the difference between 2Rx8 and 2Rx4 at 16GB DDR4-2666?

Both are dual-rank 16GB DDR4 RDIMMs but use different DRAM device widths. 2Rx8 uses wider x8 DRAM chips (fewer chips per rank), while 2Rx4 uses narrower x4 chips. 2Rx4 provides slightly better DRAM-level ECC (Chip Kill capable), while 2Rx8 is typically more cost-effective at the same capacity.

Is 840756-091 interchangeable with 835955-B21?

Yes — both are HPE 16GB DDR4-2666 2Rx8 ECC RDIMM modules with identical specifications. 840756-091 is the factory/OEM configuration variant and 835955-B21 is the option kit — they are functionally interchangeable.

Can 840756-091 be mixed with 2Rx4 16GB RDIMMs in the same server?

Mixing 2Rx4 and 2Rx8 modules in the same memory channel is generally not recommended and may result in reduced performance or compatibility warnings. Consult HPE QuickSpecs for validated mixed-configuration rules.

The HPE 840756-091 16GB DDR4-2666 2Rx8 RDIMM is a factory-configured server memory module for HPE ProLiant Gen10 platforms. Get it in stock today at a competitive price.