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Green circuit board with gold contacts and black memory chips

OWC

OWC 16GB DDR4 2666 ECC UDIMM 2Rx8 CL19 1.2V memory upgrade

SKU CH-GRA4-VMJX1

A 16 GB DDR4 2666 ECC UDIMM module with CL19 latency and 1.2 V operation, validated for Synology RackStation RS2421+ and RS2421RP+ systems

  • Total capacity16 GB (1 × 16 GB)
  • Rated speedDDR4 2666 (PC4 21300)
  • CAS latencyCL19
  • Rated voltage1.2 V
  • Buffer typeUnbuffered
  • Memory rank2Rx8
  • 16 GB capacity expands NAS multitasking headroom
  • DDR4 2666 speed matches Synology RS2421+ specifications
  • ECC protection guards data integrity in 24/7 operation
  • 2 V low voltage reduces system power draw
  • 288-pin UDIMM fits supported Synology RackStation slots

Synology RackStation memory upgrade

This OWC module adds 16GB of DDR4 ECC memory to compatible Synology RackStation RS2421+ and RS2421RP+ units. It operates at 2666MHz with a CL19 latency and runs at the standard 1.2V. The unbuffered 288-pin UDIMM format installs directly into the available memory slots.

Suited for NAS expansion, not generic PCs

The part is validated for the two listed RackStation models, so administrators expanding those systems can install it with confidence. Builders assembling custom servers or upgrading standard desktop motherboards should verify their platform accepts DDR4 ECC UDIMMs before purchasing.

ECC UDIMM with 2Rx8 organisation

Error-correcting code and a dual-rank 2Rx8 layout are the defining specifications that determine compatibility with the target Synology units. Systems requiring registered DIMMs or non-ECC memory will not support this module.

How it compares

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

Price $119.99
Cheaper than about 65% of the 21,161 comparable items (median $397.99).
Total capacity 16 GB (1 × 16 GB)
Lower than about 70% of the 20,941 comparable items (median 32 GB).
Price per GB $7.50 per GB
Cheaper than about 54% of the 20,941 comparable items (median $8.19 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 number2E6D42R816 GB
Total capacity16 GB (1 × 16 GB)
Product type288-Pin DDR4 ECC UDIMM
Performance
Rated speedDDR4 2666 (PC4 21300)
Memory
CAS latencyCL19
ECC supportYes
Buffer typeUnbuffered
Memory rank2Rx8
Heat spreaderNo
Power
Rated voltage1.2 V
Compatibility
Compatible systemsSynology RackstationRS2421+
Synology RackstationRS2421RP+

Questions about this item

Does this 288-pin DDR4 UDIMM fit the memory slots in a Synology RackStation RS2421+ or RS2421RP+?

Yes, the module is built to the 288-pin DDR4 UDIMM form factor used by those RackStation models, so it seats directly in the standard DIMM slots.

What is the correct way to install the module, and what step do people often miss?

Power off the NAS, open the chassis, align the notch on the 288-pin edge connector with the slot key, press firmly until both retention clips click, then close the case before powering on.

Will this ECC UDIMM need any firmware updates or component replacements during its service life?

The memory itself has no moving parts or firmware; it requires no scheduled maintenance or replacement unless a hardware fault occurs.

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