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Eight green 288-pin DDR4 RDIMM modules in a row

NEMIX RAM

NEMIX RAM 256GB (8x32GB) DDR4 2666 PC4-21300 ECC RDIMM memory upgrade for Synology SA6400

SKU CH-RXF4-CBDQ2

256 GB DDR4 ECC registered memory kit with eight 32 GB modules at 2666 MHz for Synology SA6400 NAS

  • Total capacity256 GB (8 × 32 GB)
  • Rated speedDDR4 2666 (PC4 21300)
  • ChipsetMajor OEM Samsung, Micron, Hynix
  • CAS latencyCL19
  • Buffer typeRegistered
  • Rated voltage1.2 V
  • 256 GB total capacity across eight 32 GB modules
  • DDR4 2666 speed rated at PC4-21300
  • ECC registered RDIMM protects data integrity
  • 2 V operation reduces power draw
  • 288-pin 2Rx4 design fits Synology SA6400

Synology SA6400 256GB DDR4 kit

This 256GB kit contains eight 32GB DDR4 2666 registered ECC RDIMMs built for the Synology SA6400 NAS. It targets administrators who need maximum supported memory capacity for virtualization, large file caches or heavy multi-user workloads on that specific platform.

Registered ECC RDIMM build

Each module is a 288-pin DDR4 RDIMM with 2Rx4 organisation, CL19 latency and 1.20V operation. Registered buffering and on-die ECC protect data integrity under sustained load, while the standard DDR4 voltage keeps power draw predictable in a densely populated chassis. No heat spreaders are fitted, so airflow across the DIMM slots remains unimpeded.

Upgrading from smaller kits

The kit replaces lower-capacity DDR4 2666 RDIMM sets when the SA6400 workload outgrows the installed memory. The jump is worth it when applications hit the current limit and the system can address the full 256GB across all eight slots. Buyers needing non-ECC memory or faster speeds should look elsewhere.

How it compares

Measured against everything we stock in Model-Specific Memory Upgrades, at today’s prices. Recalculated every night.

Price $1,643.99
Pricier than about 66% of the 21,161 comparable items (median $397.99).
Total capacity 256 GB (8 × 32 GB)
Higher than about 80% of the 20,941 comparable items (median 32 GB).
Price per GB $6.42 per GB
Cheaper than about 61% of the 20,941 comparable items (median $8.19 per GB).

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Specifications

Product
Brand nameNEMIX RAM
Product lineSynology Compatible Series NAS Memory
Model nameSynology DDR4 2666 MHz ECC RDIMM Registered Server Memory
Part numberMR21300-324K8
Total capacity256 GB (8 × 32 GB)
Product type288-Pin DDR4 RDIMM
Performance
Rated speedDDR4 2666 (PC4 21300)
Processor
ChipsetMajor OEM Samsung, Micron, Hynix
Memory
CAS latencyCL19
ECC supportYes
Buffer typeRegistered
Heat spreaderNo
Memory rank2Rx4
Power
Rated voltage1.2 V
Compatibility
Compatible systemsSynology
In the box
Included items256 GB (8 × 32 GB) DDR4 2666 MHz PC4-21300 2Rx4 1.2 V CL19 288-PIN ECC RDIMM Registered Server Memory KIT

Questions about this item

What DDR4 speed and PC4 rating does this 256GB kit run at?

The kit operates at DDR4 2666 with a PC4-21300 data-rate, so peak bandwidth is capped at that specification.

What physical slot and pin count do the eight 32GB modules need?

Each module is a 288-pin DDR4 RDIMM, requiring eight available registered DIMM slots in the Synology SA6400.

How are the modules installed and what step is often missed?

Power down the NAS, open the chassis, insert each 2Rx4 1.20 V RDIMM until the ejector clips lock, then verify all eight modules appear in DSM before closing the case.

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