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Four green 288-pin DDR4 RDIMM modules without heat spreaders

OWC

OWC 128GB (4x32GB) DDR4 2666 ECC Registered RDIMM for Synology Flashstation FS6400 HD6500 server RAM

SKU CH-R6F9-T04G4

128 GB DDR4-2666 ECC registered RDIMM kit (4 × 32 GB, CL19, 1.2 V) validated for Synology FlashStation FS6400 and HD6500 servers

  • Capacity128GB (4 x 32GB)
  • Type288-Pin DDR4 SDRAM
  • SpeedDDR4 2666 (PC4 21300)
  • CAS LatencyCL19
  • Voltage1.2V
  • ECCYes

Capacity 128GB (4 x 32GB)

Rank 2Rx4

  • 128GB total capacity with four 32GB modules installed
  • ECC registered design detects and corrects single-bit errors
  • DDR4 2666 speed runs at CL19 latency and 1.2V
  • JEDEC and RoHS compliant for warranty-safe upgrades
  • Backward compatible with 2133MHz and 2400MHz systems

Synology Flashstation FS6400 & HD6500 ECC RDIMM Kit

This OWC kit delivers 128GB of DDR4 2666 ECC Registered memory in four 32GB modules. It is built for Synology Flashstation FS6400 and HD6500 servers that require registered DIMMs with error correction. The modules run at 1.2V with CL19 latency and conform to JEDEC PC4-21300 specifications.

Registered ECC Servers Only — Not Desktop

This memory suits administrators upgrading or repairing the named Synology platforms. It will not work in standard desktop motherboards, consumer laptops, or any system that requires unbuffered or load-reduced DIMMs. Builders needing non-ECC or consumer-speed modules should select a different product line.

Tool-Free DIMM Installation With Population Rules

Installation follows the server’s standard DIMM-slot procedure: power down, open the chassis, align the 288-pin notch, and press until the latches lock. The kit is a dual-channel set, so modules must populate the correct paired slots; mis-population is the most common cause of boot failure or reduced bandwidth.

Highlights

  • 128GB total capacity with four 32GB modules installed
  • ECC registered design detects and corrects single-bit errors
  • DDR4 2666 speed runs at CL19 latency and 1.2V
  • JEDEC and RoHS compliant for warranty-safe upgrades
  • Backward compatible with 2133MHz and 2400MHz systems

Specifications

BrandOWC
Part Number2R6D42R4128S
Capacity128GB (4 x 32GB)
Type288-Pin DDR4 SDRAM
SpeedDDR4 2666 (PC4 21300)
CAS LatencyCL19
Voltage1.2V
ECCYes
Buffered/RegisteredRegistered
Rank2Rx4
Multi-channel KitDual Channel Kit
Heat SpreaderNo

Other versions of this model

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Questions about this item

Does my Synology Flashstation FS6400 or HD6500 need 288-pin DDR4 slots to accept this 128GB kit?

Yes, the modules are 288-pin DDR4 RDIMMs and require compatible registered DIMM slots in the FS6400 or HD6500.

Can I keep my existing 2133MHz or 2400MHz DDR4 ECC registered modules and add this 2666MHz kit?

The kit is backward compatible with 2133MHz and 2400MHz speeds, but all modules will run at the lowest installed speed.

How do I confirm the 128GB (4x32GB) kit is running at 2666MHz with ECC active after installation?

Check the Synology DSM memory information page; it will show 128GB total, 2666MHz speed, and ECC registered status.

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