64GB DDR4, 288-pin DIMM, 2666MHz, Registered (buffered)
Cisco UCS-MR-X64G4RSH-RF, 64 GB, DDR4, 2666 MHz, 288-pin DIMM
Cisco UCS-MR-X64G4RSH-RF. Internal memory: 64 GB, Internal memory type: DDR4, Memory clock speed: 2666 MHz, Memory form factor: 288-pin DIMM