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Two green DDR4 RDIMM modules with gold contacts and black chips, no heat spreaders

OWC

OWC 256GB (2x128GB) DDR4 2666MHz CL19 4Rx4 ECC Registered RDIMM 1.2V 288-pin Server RAM

SKU CH-7FW0-XT65W

256 GB dual-channel DDR4-2666 ECC registered server memory kit with CL19 latency, 1.2 V operation, 4Rx4 organisation and 288-pin RDIMM form factor

  • Capacity256GB (2 x 128GB)
  • Type288-Pin DDR4 ECC RDIMM
  • SpeedDDR4 2666 (PC4 21300)
  • CAS LatencyCL19
  • Voltage1.2V
  • ECCYes

Capacity 256GB (2 x 128GB)

Show 7 more configurations

Rank 4Rx4

  • ECC registered design protects data integrity in servers
  • 256GB dual-channel kit expands memory capacity for heavy workloads
  • DDR4 2666MHz CL19 speed matches enterprise platform specs
  • 2V operation reduces power draw per module
  • JEDEC and RoHS compliant for warranty-safe upgrades

Server ECC RDIMM kit

This 256GB kit provides two 128GB DDR4 2666MHz registered DIMMs with ECC for servers, workstations and NAS systems. The modules run at CL19 latency and 1.2V, conforming to JEDEC PC4-21300 specifications. They are designed for multi-channel operation in compatible enterprise platforms. This memory will not work in standard desktop computers or alongside unbuffered modules.

Thermal and power profile

Each module operates at the standard 1.2V DDR4 voltage without a heat spreader, relying on system airflow for cooling. The registered design adds a clock cycle of buffering, which slightly increases power draw compared with unbuffered DIMMs but improves signal integrity at high capacity. Acoustic output is determined by the host chassis fans rather than the memory itself.

Compliance and support

The kit is fully compliant with JEDEC standards and RoHS directives, ensuring a warranty-safe upgrade for OEM systems. OWC validates every module in its in-house lab and backs the kit with a limited lifetime warranty and free technical support. An advanced replacement program is also available for qualifying issues.

Highlights

  • ECC registered design protects data integrity in servers
  • 256GB dual-channel kit expands memory capacity for heavy workloads
  • DDR4 2666MHz CL19 speed matches enterprise platform specs
  • 2V operation reduces power draw per module
  • JEDEC and RoHS compliant for warranty-safe upgrades

Specifications

BrandOWC
Part Number2R6D44R4256P
Capacity256GB (2 x 128GB)
Type288-Pin DDR4 ECC RDIMM
SpeedDDR4 2666 (PC4 21300)
CAS LatencyCL19
Voltage1.2V
ECCYes
Buffered/RegisteredRegistered
Rank4Rx4
Multi-channel KitDual Channel Kit
Heat SpreaderNo

Other versions of this model

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Questions about this item

How do I install the 288-pin RDIMM modules and what step is often missed?

Power down the server, open the chassis, align the notch on each 128GB module with the 288-pin slot key, press firmly until the retention clips click, then enable ECC in the BIOS — skipping the BIOS step leaves error correction inactive.

What maintenance or replacement will the 4Rx4 ECC registered kit need later?

The modules have no heat spreaders and no moving parts, so no scheduled maintenance is required; replacement only occurs if a DIMM fails, at which point the matching 128GB 4Rx4 registered stick must be sourced to keep rank symmetry.

What limit appears first under sustained load with the CL19 2666MHz registered DIMMs?

The registered buffer adds one cycle of latency, so memory-controller throughput caps before the CL19 timing or 1.2V thermal envelope becomes the bottleneck.

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