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Two green DDR2 memory modules with gold contacts and silver heat spreaders

Kingston Technology Corp.

Kingston Technology Corp. KTH-XW9400K2/16G 16GB (2 x 8GB) DDR2 667 ECC Registered memory upgrade

SKU CH-YFHQ-RJHS9 MPN KTH-XW9400K2/16G

16 GB DDR2-667 ECC registered dual-rank kit for HP/Compaq workstations

  • Total capacity16 GB (2 × 8 GB)
  • Rated speedDDR2 667
  • Rated voltage1.8 V
  • Buffer typeRegistered
  • Memory rank2Rx4
  • Product type240-Pin DDR2 SDRAM
  • ECC protection prevents data corruption in critical workloads
  • Registered design improves signal integrity for stable server operation
  • Dual-rank 2Rx4 organisation maximises 16 GB capacity across two modules
  • DDR2 667 speed matches HP/Compaq workstation specifications
  • 80 V operation meets original system voltage requirements

HP/Compaq DDR2 667 Kit

This 16GB kit contains two 8GB registered ECC DDR2 667 modules built for HP and Compaq systems that require 240-pin DDR2 SDRAM. The dual-rank 2Rx4 design runs at 1.80V and matches the original HP part numbers 408855-B21 and 495605-B21. It is a direct replacement for qualified workstations and servers.

Registered ECC Only

The modules are fully buffered registered ECC memory, so they suit HP/Compaq platforms that specifically demand registered error-correcting DDR2. Systems that accept only unbuffered non-ECC DDR2 or that require a different pin count or voltage will not support this kit.

240-Pin DDR2 667 Form Factor

The 240-pin DDR2 667 interface is the single specification that decides fitment; the motherboard must accept registered ECC DDR2 at this speed and pin layout or the modules will not install or function.

How it compares

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

Price $539.99
Typical for this category: the median of 21,161 items is $397.99.
Total capacity 16 GB (2 × 8 GB)
Lower than about 70% of the 20,941 comparable items (median 32 GB).
Price per GB $33.75 per GB
Pricier than about 90% of the 20,941 comparable items (median $8.19 per GB).

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Specifications

Product
Brand nameKingston
Model nameKTH-XW9400K2/16G
Total capacity16 GB (2 × 8 GB)
Product type240-Pin DDR2 SDRAM
Performance
Rated speedDDR2 667
Memory
ECC supportYes
Buffer typeRegistered
Memory rank2Rx4
Power
Rated voltage1.8 V
Size & build
Shipping weight0.06 kg
Package size170 × 91 × 14 mm
Compatibility
Compatible systemsHP/Compaq

Questions about this item

Should I choose the 16GB kit or look for a larger capacity?

This kit provides 16GB as two 8GB modules, matching the 495605-B21 part that represents one quarter of a 64GB maximum configuration for the supported HP/Compaq systems.

What does the DDR2 667 rating mean for actual system performance?

The modules run at 667 MT/s with 1.80V voltage and registered ECC operation, so the memory controller in the target HP/Compaq workstation will operate at that speed with error correction and signal buffering active.

Does the 240-pin DDR2 interface limit the bandwidth in practice?

Yes, the 240-pin DDR2 SDRAM interface caps the data rate at 667 MT/s, and the registered 2Rx4 organisation adds one clock cycle of latency while providing the electrical buffering required by the compatible HP/Compaq platforms.

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