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Four green DDR4 ECC UDIMM sticks in static bags

OWC

OWC 64GB (4x16GB) DDR4 2666 ECC UDIMM CL19 1.2V for Synology RS3621RPxs RS3621xs+ memory upgrade

SKU CH-K1ST-STSAS

64GB DDR4 2666 ECC UDIMM kit of four 16GB modules at 1.2V CL19 for Synology RS3621RPxs and RS3621xs+ NAS systems

  • Capacity64GB (4 x 16GB)
  • Type288-Pin DDR4 ECC UDIMM
  • SpeedDDR4 2666 (PC4 21300)
  • CAS LatencyCL19
  • Voltage1.2V
  • ECCYes

Capacity 64GB (4 x 16GB)

  • Boosts NAS capacity with 64GB kit of four 16GB modules
  • ECC protection guards data integrity on Synology RS3621RPxs and RS3621xs+
  • DDR4 2666 CL19 runs at efficient 1.2V
  • JEDEC-standard unbuffered UDIMM ensures warranty-safe upgrade
  • Backward compatible with 2133 and 2400MHz systems

Synology RS3621RPxs and RS3621xs+ 64GB DDR4 ECC kit

This kit supplies 64GB of DDR4 ECC unbuffered memory across four 16GB modules for the Synology RS3621RPxs and RS3621xs+ RackStations. It targets administrators who need to maximise the supported memory capacity of these specific NAS platforms. The modules operate at 1.2V and meet JEDEC PC4-21300 specifications.

CL19 2666MHz modules with 2133/2400 backward

Each 288-pin UDIMM runs at 2666MHz with a CAS latency of 19 and a 2Rx8 organisation. The kit is validated for the two listed Synology models and will also clock down to 2133MHz or 2400MHz if the system requires it. ECC functionality provides error detection and correction for data integrity in storage workloads.

DDR4 288-pin UDIMM interface limits capacity

The DDR4 unbuffered DIMM standard used here fits the four memory slots available in the compatible RackStations, capping the upgrade at 64GB with this kit. Systems requiring registered DIMMs, higher speeds than 2666MHz, or capacities beyond four modules cannot use this memory. Buyers needing larger memory pools must choose a platform that supports registered or higher-density modules.

Highlights

  • Boosts NAS capacity with 64GB kit of four 16GB modules
  • ECC protection guards data integrity on Synology RS3621RPxs and RS3621xs+
  • DDR4 2666 CL19 runs at efficient 1.2V
  • JEDEC-standard unbuffered UDIMM ensures warranty-safe upgrade
  • Backward compatible with 2133 and 2400MHz systems

Specifications

BrandOWC
Part Number2E6D42R8064S
Capacity64GB (4 x 16GB)
Type288-Pin DDR4 ECC UDIMM
SpeedDDR4 2666 (PC4 21300)
CAS LatencyCL19
Voltage1.2V
ECCYes
Buffered/RegisteredUnbuffered
Rank2Rx8
Heat SpreaderNo
Compatible SystemSynology RackstationRS3621RPxs
Synology RackstationRS3621xs+

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Questions about this item

Will the 288-pin DDR4 modules need any firmware updates or periodic replacement after installation?

The JEDEC-standard 1.2V DDR4 2666 CL19 2Rx8 ECC UDIMMs require no firmware updates and are designed for the lifetime of the Synology RS3621RPxs or RS3621xs+ without scheduled replacement.

What limit appears first when the four 16GB sticks run at 2666 MHz continuously in a RS3621RPxs?

The memory controller caps throughput at the DDR4 2666 (PC4-21300) data rate, so sustained workloads hit that bandwidth ceiling before thermal or voltage limits are reached.

How much extra heat and power do the 64GB of ECC UDIMMs add when the NAS runs all day?

Each 1.2V module draws minimal power and has no heat spreader, so the kit adds only a small thermal load that the RS3621RPxs or RS3621xs+ chassis fans handle without audible increase.

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