The HP SAMSUNG 512MB 16ECC Alphaserver Memory ES4720-1E87A-01, MR18R162GDF0-CM8 is a single 512MB RDRAM module designed for high-performance computing. With a total capacity of 512MB spread across one module, this memory is suitable for server environments that require reliable and fast memory access. The use of ECC memory in this module ensures enhanced error correction capabilities, making it ideal for applications where data accuracy is critical. With a bus speed of PC2-6400 (DDR2-800) and Samsung quality assurance, this memory module is a dependable choice for enhancing server performance.