These are four identical 1GB DDR2 desktop RAM modules (UDIMMs) manufactured by Qimonda (a former memory division of Infineon, which ceased operations around 2009). Key Specifications (per module): • Capacity: 1GB • Type: DDR2 SDRAM • Form Factor: 240-pin UDIMM (Unbuffered DIMM, for desktop PCs – not laptop SODIMMs) • Speed: PC2-6400 (DDR2-800 MHz effective clock speed) • Configuration: 1Rx8 (Single Rank, 8 chips on one side) • CAS Latency (CL): 6 • Voltage: 1.8V • ECC: Non-ECC (unbuffered, no error correction) • Part Number: HYS64T128000EU-2.5-C2 • Additional Label Codes: PC2-6400U-666-12-D0 (common JEDEC/SPD timing code for this speed and latency) • Assembly Location: Assembled in China (as noted on the stickers)
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