We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Green circuit board with gold contacts and black memory chips, no heat spreader

OWC

OWC 16GB DDR4 2666MHz ECC UDIMM CL19 1.2V 2Rx8 288-pin Synology RS3621RPxs RS3621xs+

SKU CH-W75H-KQETT

16 GB DDR4 2666 MHz ECC UDIMM CL19 1.2 V 2Rx8 288-pin module for Synology RS3621RPxs and RS3621xs+ NAS

  • Total capacity16 GB (1 × 16 GB)
  • Rated speedDDR4 2666 (PC4 21300)
  • CAS latencyCL19
  • Rated voltage1.2 V
  • Buffer typeUnbuffered
  • Memory rank2Rx8
  • 16 GB capacity boosts NAS multitasking headroom
  • ECC UDIMM protects data integrity in Synology RackStation
  • 2666 MHz DDR4 speed matches RS3621RPxs and RS3621xs+ specs
  • 2 V operation keeps power draw low
  • 288-pin CL19 2Rx8 module installs without tools

Synology RS3621RPxs and RS3621xs+ memory upgrade

This 16GB DDR4 ECC UDIMM is validated for Synology RackStation RS3621RPxs and RS3621xs+ systems. It installs as a single module to expand NAS memory capacity. Buyers needing higher-density kits or registered DIMMs for other platforms should verify their hardware requirements first.

DDR4 2666 CL19 ECC unbuffered specification

The module runs at DDR4 2666 (PC4-21300) with CL19 latency at 1.2V. It uses a 2Rx8 288-pin unbuffered layout with on-die error correction. Systems that require registered or load-reduced memory cannot use this part.

JEDEC standard compliance and backward speed support

The DIMM meets JEDEC and RoHS standards for warranty-safe installation. It also operates at 2133MHz and 2400MHz when the host platform dictates lower speeds. No heat spreader is included, so airflow in the chassis must be adequate.

How it compares

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

Price $113.99
Cheaper than about 66% 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 $7.12 per GB
Cheaper than about 57% 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 RackstationRS3621RPxs
Synology RackstationRS3621xs+

Questions about this item

What does the 2666MHz speed mean for my Synology RS3621RPxs or RS3621xs+ NAS?

The module runs at 2666MHz, matching the native memory controller speed of the RS3621RPxs and RS3621xs+ so the system operates at its rated bandwidth without downclocking.

How does the PC4-21300 designation relate to the DDR4 2666MHz interface in practice?

PC4-21300 is the JEDEC standard name for DDR4 2666MHz; the module plugs into the 288-pin UDIMM slots and will also run at 2133MHz or 2400MHz if the system requires a lower speed.

Will this 288-pin UDIMM fit the memory slots in my RS3621RPxs or RS3621xs+?

Yes, it is a standard 288-pin DDR4 ECC UDIMM, the exact form factor used by the RS3621RPxs and RS3621xs+ for memory expansion.

More in Model-Specific Memory Upgrades

Similar items