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Green rectangular DDR4 RDIMM module with gold edge connectors and black memory chips, no heat spreader

OWC

OWC 16GB DDR4 2666 ECC Registered RDIMM CL19 1.2V 2Rx4

SKU CH-5N5M-1BNH9

16 GB DDR4 2666 ECC registered RDIMM for servers, workstations and NAS, CL19 1.2 V 2Rx4

  • Total capacity16 GB
  • Rated speedDDR4 2666 (PC4 21300)
  • CAS latencyCL19
  • Rated voltage1.2 V
  • Buffer typeRegistered
  • Memory rank2Rx4

Capacity 16GB

Rank 2Rx4

  • ECC registered design protects data integrity in servers and workstations
  • 16 GB capacity expands memory headroom for demanding workloads
  • DDR4 2666 MHz speed with CL19 latency delivers responsive performance
  • 2 V operation reduces power draw and heat output
  • JEDEC and RoHS compliant for warranty-safe upgrades

16GB ECC Registered DDR4 for Synology NAS

This 16GB DDR4 2666 MHz ECC Registered RDIMM is built for Synology FlashStation FS6400 and HIGH Density HD6500 systems. It replaces the OEM D4RD-2666-16G and D4ER01-16G modules directly. The module targets administrators who need validated server memory for 24/7 NAS workloads.

288-pin Registered DIMM with JEDEC compliance

The stick uses a 288-pin DDR4 form factor without a heat spreader, running at 1.2V with CL19 latency and a 2Rx4 organisation. Registered buffering and ECC support protect data integrity in multi-module configurations. Backward compatibility with 2133 MHz and 2400 MHz platforms allows mixed-speed deployments.

Upgrades from lower-capacity or non-ECC DIMMs

Installing this module adds 16GB of error-correcting capacity to compatible Synology units, extending the service life of existing appliances. The jump is worthwhile when current memory limits virtual-machine counts or file-cache performance. It will not work in standard desktop boards or alongside unbuffered or load-reduced DIMMs.

How it compares

Measured against everything we stock in ECC Server RAM, at today’s prices. Recalculated every night.

Price $94.99
Cheaper than about 71% of the 6,523 comparable items (median $188.99).
Total capacity 16 GB
Lower than about 60% of the 6,064 comparable items (median 32 GB).
Price per GB $5.94 per GB
Cheaper than about 64% of the 6,064 comparable items (median $7.25 per GB).

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Specifications

Product
Brand nameOWC
Part number2R6D42R416 GB
Total capacity16 GB
Product type288-Pin DDR4 SDRAM
Performance
Rated speedDDR4 2666 (PC4 21300)
Memory
CAS latencyCL19
ECC supportYes
Buffer typeRegistered
Memory rank2Rx4
Heat spreaderNo
Power
Rated voltage1.2 V

Other versions of this model

5 more in the same range

Questions about this item

What speed does the DDR4 2666 PC4-21300 interface actually run at in a system that only supports 2133 MHz?

The module is backward compatible and will operate at 2133 MHz when installed in a platform limited to that speed.

Does the 288-pin registered DIMM fit a standard desktop motherboard slot?

No. This registered ECC DIMM is designed for server, workstation and NAS systems and will not work in standard desktop computers.

What is the correct way to install this 16 GB 2Rx4 module, and what mistake should I avoid?

Align the notch with the slot key, press firmly until the latches click, and do not mix this registered DIMM with unbuffered or load-reduced memory.

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