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NEMIX RAM

NEMIX RAM 64GB (4x16GB) DDR4 2666 ECC UDIMM CL19 1.2V 288-Pin Synology RS3621RPxs

SKU CH-74JJ-CREY2

A 64 GB kit of four 16 GB DDR4 2666 ECC UDIMM modules at CL19 and 1.2 V, validated for Synology RS3621RPxs NAS

  • Total capacity64 GB (4 × 16 GB)
  • Rated speedDDR4 2666 (PC4 21300)
  • ChipsetMajor OEM Samsung, Micron, Hynix
  • CAS latencyCL19
  • Buffer typeUnbuffered
  • Rated voltage1.2 V
  • 64GB kit expands Synology NAS capacity
  • ECC unbuffered design protects data integrity
  • DDR4 2666 CL19 speed matches system spec
  • 2V low voltage reduces power draw
  • 288-pin UDIMM form factor fits RS3621RPxs

Synology RS3621RPxs 64GB DDR4 ECC kit

This 64GB kit contains four 16GB DDR4 2666 UDIMMs validated for the Synology RS3621RPxs RackStation. Each module runs at 1.20V with CL19 latency and includes on-die ECC for data integrity in NAS workloads. The 288-pin unbuffered design fits the system’s native memory slots without registration overhead. IT teams can install the kit in minutes to reach the platform’s supported capacity ceiling.

Capacity and headroom for multi-user NAS

Four 16GB 2Rx8 modules populate every available slot, delivering the full 64GB the RS3621RPxs can address. This headroom handles concurrent file shares, virtual-machine storage and Docker containers without paging to disk. Workloads that exceed 64GB will require a higher-capacity platform, as the memory controller does not support larger UDIMMs or additional channels. The kit therefore matches the system’s hard limit rather than leaving empty slots for future growth.

Thermals noise and power draw in normal use

Modules operate at the standard 1.20V DDR4 voltage and have no heat spreaders, relying on the chassis airflow directed across the DIMM banks. Under typical NAS loads the sticks stay within JEDEC thermal limits without adding audible fan noise. Power draw scales linearly with active rank count, so the 2Rx8 organisation keeps per-module consumption predictable during sustained read-write cycles. No extra cooling or voltage tuning is required for continuous operation.

How it compares

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

Price $552.99
Typical for this category: the median of 21,161 items is $397.99.
Total capacity 64 GB (4 × 16 GB)
Higher than about 60% of the 20,941 comparable items (median 32 GB).
Price per GB $8.64 per GB
Typical for this category: the median of 20,941 items is $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 numberME21300-628K4
Total capacity64 GB (4 × 16 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 items64 GB (4 × 16 GB) DDR4 2666 MHz PC4-21300 2Rx8 1.2 V CL19 288-PIN ECC Unbuffered UDIMM KIT

Questions about this item

Will the 288-pin DDR4 2666 ECC UDIMM modules work with the existing memory slots in my Synology RS3621RPxs?

Yes, the 288-pin DDR4 2666 ECC UDIMM modules match the slot specification for the Synology RS3621RPxs and are designed to operate alongside any compatible memory already installed.

How can I verify the 64GB kit is running at 2666MHz with CL19 latency after installation?

Check the system information or resource monitor in DSM; it will report the installed memory speed as 2666MHz and CAS latency as CL19 when the kit is operating correctly.

Does the package include all four 16GB modules, or do I need to buy additional sticks to reach 64GB?

The package contains the complete 64GB kit as four 16GB modules, so no additional memory sticks are required.

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