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Two green 288-pin DDR5 RDIMM modules without heat spreaders

NEMIX RAM

NEMIX RAM MR38400-744K2 256GB (2x128GB) DDR5 4800 CL40 ECC RDIMM memory upgrade

SKU CH-HY8E-RBJDH

256 GB DDR5 server memory kit with two 128 GB registered ECC modules at 4800 MHz CL40

  • Total capacity256 GB (2 × 128 GB)
  • Rated speedDDR5 4800 (PC5 38400)
  • ChipsetMajor OEM Samsung, Micron, Hynix
  • CAS latencyCL40
  • Buffer typeRegistered
  • Rated voltage1.1 V
  • 256 GB total capacity from two 128 GB modules
  • DDR5 4800 speed delivers PC5-38400 bandwidth
  • ECC registered design protects data integrity in servers
  • 1 V operation reduces power draw per module
  • Validated for Dell PowerEdge XE8640 rack servers

Dell PowerEdge XE8640 memory kit

This 256GB kit contains two 128GB DDR5 4800 CL40 ECC RDIMM modules built for the Dell PowerEdge XE8640 rack server. Registered buffering and on-die ECC protect data integrity in mission-critical workloads. The kit targets IT teams upgrading memory capacity in validated Dell server configurations. Buyers needing non-ECC or unbuffered DIMMs for desktop platforms cannot use this product.

Registered DDR5 at 1.10 V

Each module operates at the standard DDR5 server voltage of 1.10 V with a CAS latency of CL40. Registered signalling reduces electrical load on the memory controller, helping thermal headroom in dense chassis. No heat spreaders are fitted, so airflow across the 288-pin DIMMs must be provided by the server cooling design. Systems requiring lower latency or active cooling on the modules themselves are not addressed by this kit.

Two-module validated kit

The package supplies a matched pair of 128GB 4Rx4 RDIMMs tested for compatibility with the Dell PowerEdge XE8640. No additional software, cables or mounting hardware are included. Installation follows the server manufacturer memory population rules. Environments that require single-module upgrades, mixed-capacity populations or third-party qualification reports are not covered by this bundle.

How it compares

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

Price $7,775.99
Pricier than about 84% of the 21,161 comparable items (median $397.99).
Total capacity 256 GB (2 × 128 GB)
Higher than about 80% of the 20,941 comparable items (median 32 GB).
Price per GB $30.37 per GB
Pricier than about 87% of the 20,941 comparable items (median $8.19 per GB).

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Specifications

Product
Brand nameNEMIX RAM
Product lineDell Server/Workstation Compatible Series Memory
Model nameDell DDR5 4800 MHz ECC RDIMM Registered Server Memory
Part numberMR38400-744K2
Total capacity256 GB (2 × 128 GB)
Product type288-Pin DDR5 RDIMM
Performance
Rated speedDDR5 4800 (PC5 38400)
Processor
ChipsetMajor OEM Samsung, Micron, Hynix
Memory
CAS latencyCL40
ECC supportYes
Buffer typeRegistered
Heat spreaderNo
Memory rank4Rx4
Power
Rated voltage1.1 V
Compatibility
Compatible systemsDell
In the box
Included items256 GB (2 × 128 GB) DDR5 4800 MHz PC5-38400 4Rx4 1.1 V CL40 288-PIN ECC RDIMM Registered Server Memory KIT

Questions about this item

How do I install the 288-pin DDR5 RDIMM modules in the Dell PowerEdge XE8640, and which step is most often missed?

Power down the server, open the chassis, align each 288-pin module with the keyed slot, press firmly until the ejector tabs click, then verify in BIOS that both 128 GB sticks register at 4800 MT/s and CL40; the step most often missed is seating both modules fully so the tabs latch on both sides.

What maintenance or replacement will the 256 GB ECC RDIMM kit need over its service life?

The modules have no heat spreaders and no moving parts, so routine maintenance is limited to keeping server airflow clean; replacement is only required if a correctable ECC error count rises or a module fails, at which point the lifetime replacement covers a swap.

What limit appears first when the 4Rx4 registered DIMMs run sustained workloads at 1.1 V?

The primary limit is the DDR5 4800 MT/s bandwidth ceiling combined with CL40 latency; thermals stay within spec at 1.1 V, so throughput and latency bounds are reached before voltage or temperature throttling occurs.

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