HP 500668-S21, 1 GB, 1 x 1 GB, DDR3, 1333 MHz, 240-pin DIMM HP 500668-S21. Component for: PC/Server, Internal memory: 1 GB, Memory layout (modules x size): 1 x 1 GB, Internal memory type: DDR3, Memory clock speed: 1333 MHz, Memory form factor: 240-pin DIMM, CAS latency: 9, ECC