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Two green 288-pin DDR4 RDIMM modules with black chips, no heat spreaders

OWC

OWC 256GB (2x128GB) DDR4 2933MHz CL21 4Rx4 ECC Registered RDIMM 1.2V 288-pin server RAM

SKU CH-1ZAZ-FBWP5

A 256 GB dual-channel DDR4 ECC registered RDIMM kit running at 2933 MHz with CL21 latency for servers and workstations

  • Capacity256GB (2 x 128GB)
  • Type288-Pin DDR4 ECC RDIMM
  • SpeedDDR4 2933 (PC4 23400)
  • CAS LatencyCL21
  • Voltage1.2V
  • ECCYes

Capacity 256GB (2 x 128GB)

Show 4 more configurations

Rank 4Rx4

  • 256 GB total capacity from two 128 GB modules
  • DDR4 2933 MHz speed with CL21 latency for responsive server workloads
  • ECC registered 4Rx4 design protects data integrity in workstations and NAS systems
  • JEDEC and RoHS compliant at 1.2 V for warranty-safe upgrades
  • Backward compatible with 2133, 2400 and 2666 MHz platforms

256GB Dual-Channel Server Memory Kit

This OWC kit provides 256GB of DDR4 2933MHz ECC Registered RDIMM across two 128GB modules. It targets administrators upgrading servers, workstations or NAS systems that require registered error-correcting memory. The modules operate at 1.2V with CL21 latency and conform to JEDEC PC4-23400 specifications.

Suited For Registered ECC Platforms Only

These modules suit systems designed for 4Rx4 registered DIMMs with ECC functionality. They will not work in standard desktop computers or laptops that accept only unbuffered non-ECC memory. Builders needing unbuffered DIMMs or consumer SO-DIMM form factors must select a different product line.

Registered ECC With 4Rx4 Organization

The decisive specification is the 4Rx4 registered ECC architecture combined with 288-pin DDR4 form factor. This organization determines motherboard and chipset compatibility; verify that your platform supports quad-rank registered modules before purchase.

Highlights

  • 256 GB total capacity from two 128 GB modules
  • DDR4 2933 MHz speed with CL21 latency for responsive server workloads
  • ECC registered 4Rx4 design protects data integrity in workstations and NAS systems
  • JEDEC and RoHS compliant at 1.2 V for warranty-safe upgrades
  • Backward compatible with 2133, 2400 and 2666 MHz platforms

Specifications

BrandOWC
Part Number2R9D44R4256P
Capacity256GB (2 x 128GB)
Type288-Pin DDR4 ECC RDIMM
SpeedDDR4 2933 (PC4 23400)
CAS LatencyCL21
Voltage1.2V
ECCYes
Buffered/RegisteredRegistered
Rank4Rx4
Multi-channel KitDual Channel Kit
Heat SpreaderNo

Other versions of this model

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Same family, different memory, cooler or clock — compare before you commit.

Questions about this item

What type of system is required for this 288-pin DDR4 ECC Registered RDIMM kit to function?

This kit requires a server, workstation, or NAS system that supports 288-pin DDR4 ECC Registered memory; it will not work in standard desktop computers.

How does this 2933MHz CL21 kit behave when installed alongside existing 2400MHz modules?

The kit is backward compatible with 2133MHz, 2400MHz, and 2666MHz speeds, so it will downclock to match the slower modules already installed.

How can I verify the 256GB kit is running at the correct 2933MHz speed after installation?

Check the memory speed reported in your system BIOS or UEFI firmware; it should display 2933MHz or PC4-23400 when the kit operates at its rated specification.

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