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Green rectangular DDR4 RDIMM module with black chips on both sides and gold edge connectors

OWC

OWC 128GB DDR4 2933 ECC Registered RDIMM 2R9D48R4128G memory upgrade

SKU CH-NMBJ-FB4AP

A single 128GB DDR4 2933 ECC registered RDIMM for compatible ASRock server motherboards

  • Total capacity128 GB
  • Rated speedDDR4 2933 (PC4 23400)
  • CAS latency21
  • Rated voltage1.2 V
  • Buffer typeRegistered
  • Memory rank8Rx4
  • 128GB capacity expands server memory headroom
  • DDR4 2933 speed boosts data throughput for demanding workloads
  • ECC registered design detects and corrects errors to protect critical data
  • 2V operation lowers power draw and heat in dense configurations
  • Compatible with multiple ASRock server boards including WC621D8-NL

Server ECC Registered Memory Upgrade

This 128GB DDR4 module is an ECC Registered RDIMM built for ASRock server motherboards including the WC621D8-NL, EP2C622D24LM2, EPC621D4I-2M, EPC621D6U-2T16R and WC621D8A-2T. It is intended for workstations, servers and NAS systems that require registered error-correcting memory. It will not work in standard desktop computers and cannot be mixed with unbuffered or load-reduced modules.

DDR4 2933 Speed and Backward Compatibility

The module runs at DDR4 2933 (PC4-23400) with a CAS latency of 21 and operates at 1.2V. It is backward compatible with systems running at 2133MHz, 2400MHz and 2666MHz, allowing it to downclock automatically when installed in platforms that do not support the maximum rated speed.

Single-Module 128GB Density and 288-Pin Form Factor

A single 8Rx4 rank module delivers the full 128GB capacity, leaving additional DIMM slots free for future expansion. The 288-pin registered DIMM form factor fits standard server memory sockets without a heat spreader, simplifying installation in dense chassis. JEDEC and RoHS compliance ensures a warranty-safe upgrade for qualified ASRock platforms.

How it compares

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

Price $630.99
Pricier than about 55% of the 21,161 comparable items (median $397.99).
Total capacity 128 GB
Higher than about 70% of the 20,941 comparable items (median 32 GB).
CAS latency 21
Lower than about 63% of the 483 comparable items (median 22).
Price per GB $4.93 per GB
Cheaper than about 78% of the 20,941 comparable items (median $8.19 per GB).

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Specifications

Product
Brand nameOWC
Part number2R9D48R4128G
Total capacity128 GB
Product type288-Pin DDR4 ECC RDIMM
Performance
Rated speedDDR4 2933 (PC4 23400)
Memory
CAS latency21
ECC supportYes
Buffer typeRegistered
Memory rank8Rx4
Heat spreaderNo
Power
Rated voltage1.2 V

Questions about this item

Should I choose this single 128GB module or multiple smaller modules to reach my target capacity?

This is a single 128GB DDR4 2933 ECC Registered RDIMM. If your ASRock server board has enough 288-pin slots and supports 128GB per slot, one module is the simplest upgrade. Add more identical modules only if you need total capacity beyond 128GB.

What does the 2933MHz speed rating deliver once the module is installed in my ASRock server?

The module runs at DDR4 2933 (PC4-23400) with CL21 latency at 1.2V. On compatible ASRock boards such as the WC621D8-NL it will operate at that rated speed, providing the bandwidth and error-correction expected for registered server workloads.

How does the DDR4 2933 interface limit performance in practice?

The 288-pin DDR4 interface caps transfer rate at 2933 MT/s (PC4-23400). The module is backward compatible with 2133, 2400 and 2666 MT/s buses, so it will down-clock automatically if the motherboard or CPU memory controller cannot run at 2933.

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