HP 815101-B21, 64 GB, 1 x 64 GB, DDR4, 2666 MHz, 288-pin DIMM HP 815101-B21. Component for: PC/server, Internal memory: 64 GB, Memory layout (modules x size): 1 x 64 GB, Internal memory type: DDR4, Memory clock speed: 2666 MHz, Memory form factor: 288-pin DIMM, CAS latency: 19