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Four green 288-pin DDR4 RDIMM modules in a row

OWC

OWC 64GB (4x16GB) DDR4 2666 ECC Registered RDIMM for Synology FlashStation FS6400 HD6500 server RAM

SKU CH-Q1WE-TWA0A

A 64 GB DDR4-2666 ECC registered quad-kit validated for Synology FlashStation FS6400 and HD6500 servers

  • Capacity64GB (4 x 16GB)
  • Type288-Pin DDR4 SDRAM
  • SpeedDDR4 2666 (PC4 21300)
  • CAS LatencyCL19
  • Voltage1.2V
  • ECCYes

Capacity 64GB (4 x 16GB)

Rank 2Rx4

  • 64GB total capacity from four 16GB modules
  • DDR4 2666 MHz PC4-21300 speed with CL19 latency
  • ECC Registered 2Rx4 design for server data integrity
  • 2V low-voltage operation reduces power draw
  • JEDEC-standard 288-pin RDIMM form factor fits Synology FS6400 and HD6500

Synology FlashStation FS6400 and HD6500 upgrade

This OWC kit provides 64 GB of DDR4 2666 ECC registered memory in four 16 GB modules. It is built for Synology FlashStation FS6400 and HIGH Density HD6500 servers that require registered DIMMs. The memory will not work in standard desktop computers or systems that need unbuffered or load-reduced modules.

JEDEC and RoHS compliant registered DIMMs

Each 288-pin module runs at 1.2 V with CL19 latency and a 2Rx4 organisation. The kit meets JEDEC PC4-21300 specifications and is backward compatible with 2133 MHz and 2400 MHz bus speeds. ECC registration adds error correction and signal buffering for stable operation in multi-DIMM server configurations.

Tool-free installation in supported NAS bays

Insert the modules into the server's DIMM slots until the retention clips engage; no heat spreaders are present to interfere with tight spacing. The only common issue is attempting to mix these registered DIMMs with unbuffered or load-reduced memory, which the platform will reject at POST.

Highlights

  • 64GB total capacity from four 16GB modules
  • DDR4 2666 MHz PC4-21300 speed with CL19 latency
  • ECC Registered 2Rx4 design for server data integrity
  • 2V low-voltage operation reduces power draw
  • JEDEC-standard 288-pin RDIMM form factor fits Synology FS6400 and HD6500

Specifications

BrandOWC
Part Number2R6D42R4064S
Capacity64GB (4 x 16GB)
Type288-Pin DDR4 SDRAM
SpeedDDR4 2666 (PC4 21300)
CAS LatencyCL19
Voltage1.2V
ECCYes
Buffered/RegisteredRegistered
Rank2Rx4
Multi-channel KitDual Channel Kit
Heat SpreaderNo

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Questions about this item

Will the 288-pin DDR4 RDIMMs need any firmware updates or replacement after installation?

The modules are JEDEC-standard and ROHS compliant with a limited lifetime warranty, so no firmware updates or scheduled replacements are required after correct installation.

What limits sustained throughput on the 2666 MHz CL19 registered kit?

The CL19 latency at 2666 MHz and the registered buffer add one cycle per command, which becomes the first bottleneck under continuous heavy workloads.

How much heat and power does the 1.2 V 4-module kit produce running all day?

Each 16 GB module runs at 1.2 V without a heat spreader, so total power draw stays low and passive airflow in the FS6400 or HD6500 chassis keeps temperatures in check.

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