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OWC

OWC 256GB (8x32GB) DDR4 2666 ECC Registered RDIMM NAS SA6400 Server RAM

SKU CH-4EAJ-ZC87J

Eight 32 GB DDR4 2666 ECC registered RDIMMs totalling 256 GB for Synology SA6400 NAS and compatible servers

  • Total capacity256 GB (8 × 32 GB)
  • Rated speedDDR4 2666 (PC4 21300)
  • CAS latencyCL19
  • Rated voltage1.2 V
  • Buffer typeRegistered
  • Memory rank2Rx4

Capacity 256GB (8 x 32GB)

  • ECC registered design protects data integrity in servers
  • 256GB total capacity across eight 32GB modules for heavy workloads
  • DDR4 2666 CL19 at 1.2V delivers efficient performance
  • JEDEC and RoHS compliant for warranty-safe upgrades
  • Backward compatible with 2133MHz and 2400MHz systems

OWC 256GB DDR4 2666 ECC Registered Kit

This 256GB kit contains eight 32GB DDR4 2666 registered DIMMs built for Synology SA6400 NAS units and compatible servers. ECC registered memory detects and corrects single-bit errors to protect data integrity in always-on workloads. It will not work in standard desktop computers or alongside unbuffered or load-reduced modules. Buyers needing non-ECC or consumer DIMMs should look elsewhere.

Capacity and headroom for NAS workloads

Eight modules populate eight slots to deliver 256GB total capacity at 2666MHz CL19. The kit runs at 1.2V and is backward compatible with 2133MHz and 2400MHz bus speeds. Headroom is defined by the 288-pin registered form factor and the SA6400 memory controller; larger configurations or faster speeds are not supported by this platform. Systems requiring more than 256GB or higher-frequency modules cannot use this kit.

JEDEC compliance and lifetime support

Modules meet JEDEC and RoHS standards for a warranty-safe upgrade without voiding the original system warranty. OWC provides a limited lifetime warranty with free technical support and an advanced replacement programme. No heat spreaders are included; cooling relies on chassis airflow. The bundle contains only the eight memory modules — no software, cables or additional accessories are supplied.

How it compares

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

Price $1,785.99
Pricier than about 85% of the 6,523 comparable items (median $188.99).
Total capacity 256 GB (8 × 32 GB)
Higher than about 90% of the 6,064 comparable items (median 32 GB).
Price per GB $6.98 per GB
Typical for this category: the median of 6,064 items is $7.25 per GB.

New to this? Buying memory and SSDs with crypto — what to check, what it costs to pay, and what is never asked for.

Specifications

Product
Brand nameOWC
Part number2R6D42R4256K
Total capacity256 GB (8 × 32 GB)
Product type288-Pin DDR4 SDRAM
Performance
Rated speedDDR4 2666 (PC4 21300)
Memory
CAS latencyCL19
ECC supportYes
Buffer typeRegistered
Memory rank2Rx4
Kit configurationDual Channel Kit
Heat spreaderNo
Power
Rated voltage1.2 V

Other versions of this model

5 more in the same range

Questions about this item

Will the 2666 MHz RDIMMs run reliably alongside my existing 2133 MHz or 2400 MHz ECC registered modules?

Yes — the kit is backward compatible with 2133 MHz and 2400 MHz DDR4 ECC registered DIMMs; all modules will operate at the speed of the slowest installed kit.

How can I verify the 256 GB kit is detected and ECC is active after installation in my SA6400?

Check the DSM Resource Monitor or BIOS POST screen — it should show 256 GB total at 2666 MHz with ECC status reported as enabled or corrected errors counting.

Does the 8-module box include any heat spreaders, cables or tools, or must I buy them separately?

The package contains only the eight 32 GB 288-pin DDR4 RDIMMs (CL19, 1.2 V, 2Rx4); no heat spreaders, cables or installation tools are included.

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