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Green circuit board with black memory chips in a single row, gold edge connector, no heat spreader

NEMIX RAM

NEMIX RAM 16GB DDR4 2666 ECC UDIMM CL19 1.2V 2Rx8 288-Pin memory upgrade

SKU CH-ZHDJ-EV4DY

16 GB DDR4 2666 ECC UDIMM for Synology RS2421+/RS2421RP+ NAS, CL19, 1.2 V, 2Rx8, 288-pin

  • Total capacity16 GB
  • Rated speedDDR4 2666 (PC4 21300)
  • ChipsetMajor OEM Samsung, Micron, Hynix
  • CAS latencyCL19
  • Buffer typeUnbuffered
  • Rated voltage1.2 V
  • ECC protection prevents data errors in critical workloads
  • 2666 MHz DDR4 speed matches Synology RS2421+ specifications
  • 16 GB single module simplifies capacity expansion
  • 2 V operation reduces power draw and heat
  • 288-pin UDIMM form factor fits compatible NAS slots

Synology Compatible 16GB DDR4 ECC Module

This NEMIX RAM module provides 16GB of DDR4 2666 ECC unbuffered memory built for Synology RackStation RS2421+ and RS2421RP+ NAS systems. It operates at 1.20V with CL19 latency and uses a 2Rx8 rank configuration on a standard 288-pin UDIMM form factor.

Upgrading from non-ECC or lower-capacity sticks

The jump is worth it when your NAS workload demands error-correcting code memory for data integrity and you need a single 16GB module to fill an empty slot or replace a smaller DIMM. Systems already running matched ECC pairs at this speed will not gain additional bandwidth from this addition.

Verify your NAS model and slot availability

Confirm the unit is a Synology RackStation RS2421+ or RS2421RP+ before ordering, as compatibility is validated for those models. Check how many UDIMM slots are free and whether the existing memory uses the same 2666MHz speed and ECC unbuffered type to avoid mixing incompatible modules.

How it compares

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

Price $117.99
Cheaper than about 65% of the 21,161 comparable items (median $397.99).
Total capacity 16 GB
Lower than about 70% of the 20,941 comparable items (median 32 GB).
Price per GB $7.37 per GB
Cheaper than about 55% 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 nameNEMIX RAM
Product lineSynology Compatible Series NAS Memory
Model nameSynology DDR4 2666 MHz ECC Unbuffered UDIMM
Part numberME21300-628K1
Total capacity16 GB
Product type288-Pin DDR4 ECC UDIMM
Performance
Rated speedDDR4 2666 (PC4 21300)
Processor
ChipsetMajor OEM Samsung, Micron, Hynix
Memory
CAS latencyCL19
ECC supportYes
Buffer typeUnbuffered
Heat spreaderNo
Memory rank2Rx8
Power
Rated voltage1.2 V
Compatibility
Compatible systemsSynology
In the box
Included items16 GB (1 × 16 GB) DDR4 2666 MHz PC4-21300 2Rx8 1.2 V CL19 288-PIN ECC Unbuffered UDIMM

Questions about this item

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

Yes, the module is a 288-pin DDR4 ECC UDIMM designed for those Synology RackStation models.

What is the correct way to seat the 1.2 V CL19 module so the system recognises the full 16 GB?

Align the notch with the slot key, press firmly until both retention clips click, then verify 16 GB appears in the DSM memory section.

When should the Samsung, Micron or Hynix 2Rx8 chips be replaced under sustained NAS workloads?

Only if DSM reports correctable ECC errors or memory test failures; otherwise the module is rated for continuous operation.

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