System MemoryYour system supports DDR3 unbuffered ECC DIMMs (ECC UDIMMs), registered DIMMs (RDIMMs), and load reducedDIMMs (LRDIMMs). It supports DDR3 and DDR3L voltage specifications.NOTE: MT/s indicates DIMM speed in MegaTransfers per second.Memory bus operating frequency can be 1600 MT/s, 1333 MT/s, 1066 MT/s, or 800 MT/s depending on:• DIMM type (UDIMM, RDIMM, or LRDIMM)NOTE: PowerEdge R720xd with 3.5 inch hard-drive configuration does not support LRDIMMs due to thermallimitations.• DIMM configuration (number of ranks)• maximum frequency of the DIMMs• number of DIMMs populated per channel• DIMM operating voltage• system profile selected (for example, Performance Optimized, Custom, or Dense Configuration Optimized)• maximum supported DIMM frequency of the processorsThe system contains 24 memory sockets split into two sets of 12 sockets, one set per processor. Each 12-socket set isorganized into four channels. In each channel, the release levers of the first socket are marked white, the second socketblack, and the third socket green.NOTE: DIMMs in sockets A1 to A12 are assigned to processor 1 and DIMMs in sockets B1 to B12 are assigned toprocessor 2.43
