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Two green DDR4 ECC UDIMM modules with gold contacts

OWC

OWC 16GB (2x8GB) DDR4 2666 ECC UDIMM for Synology RS4017xs+ RS4021xs+ memory upgrade

SKU CH-CEYK-9D113

16 GB DDR4-2666 ECC UDIMM kit (2×8 GB, CL19, 1.2 V) validated for Synology RS4017xs+ and RS4021xs+ NAS

  • Capacity16GB (2 x 8GB)
  • Type288-Pin DDR4 ECC UDIMM
  • SpeedDDR4 2666 (PC4 21300)
  • CAS LatencyCL19
  • Voltage1.2V
  • ECCYes

Capacity 16GB (2 x 8GB)

  • Boosts NAS capacity with 16GB dual-channel kit
  • ECC protection guards data integrity in Synology RackStations
  • JEDEC-standard 2666MHz DDR4 runs at efficient 1.2V
  • Validated for RS4017xs+ and RS4021xs+ compatibility
  • Backward compatible with 2133MHz and 2400MHz systems

OWC 16GB DDR4 2666 ECC kit for Synology RS4017xs+

This kit adds 16GB of DDR4 2666 ECC UDIMM memory across two 8GB modules. It is built for Synology RackStation RS4017xs+ and RS4021xs+ systems that require JEDEC-standard unbuffered ECC memory. The CL19 timing and 1.2V operation match the platform specifications. Buyers needing registered DIMMs or non-ECC memory should choose a different product.

JEDEC-standard DDR4 2666 at 1.2V

Each module runs at the rated 2666MHz speed with CL19 latency while drawing only 1.2V. ECC circuitry detects and corrects single-bit errors to protect data integrity in NAS workloads. The unbuffered design keeps the signal path short for broad compatibility with the listed RackStation models. Backward compatibility allows use in slots rated for 2133MHz or 2400MHz DDR4.

Two matched 8GB modules tested for warranty-safe

The paired modules are validated together to ensure stable dual-channel operation in the target Synology systems. OWC tests every module in-house and backs the kit with a limited lifetime warranty and free technical support. No heat spreaders are included, keeping the low-profile form factor compatible with dense server chassis. The kit contains only the two memory modules; no tools or software are bundled.

Highlights

  • Boosts NAS capacity with 16GB dual-channel kit
  • ECC protection guards data integrity in Synology RackStations
  • JEDEC-standard 2666MHz DDR4 runs at efficient 1.2V
  • Validated for RS4017xs+ and RS4021xs+ compatibility
  • Backward compatible with 2133MHz and 2400MHz systems

Specifications

BrandOWC
Part Number2E6D41R8016P
Capacity16GB (2 x 8GB)
Type288-Pin DDR4 ECC UDIMM
SpeedDDR4 2666 (PC4 21300)
CAS LatencyCL19
Voltage1.2V
ECCYes
Buffered/RegisteredUnbuffered
Rank1Rx8
Heat SpreaderNo
Compatible SystemSynology RackstationRS4017xs+
Synology RackstationRS4021xs+

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Questions about this item

How do I install the 288-pin DDR4 ECC UDIMM modules in my Synology RS4017xs+ and what step is often missed?

Power off the NAS, unplug it, open the chassis, locate the memory slots, align the notch on each 288-pin module with the slot key, press down firmly until the retention clips click on both sides, then reassemble. The step often missed is fully seating both ends so the clips engage automatically.

What maintenance or replacement will this 16GB DDR4 2666 kit need over its service life?

No scheduled maintenance is required for the modules themselves. Keep the NAS vents clear of dust and ensure the cooling fans run normally so the 1.2V DIMMs stay within thermal limits. Replacement is only necessary if a module fails or you need more capacity later.

What limit appears first when the RS4021xs+ runs sustained workloads with this CL19 memory?

The memory controller will operate at the rated 2666 MT/s with CL19 latency. Under continuous heavy load the first limit encountered is typically the NAS thermal envelope or the CPU core count, not the bandwidth of these 1.2V ECC UDIMMs.

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