DTM68138-S is an Unbuffered 1Gx64 memory module, which conforms to JEDEC's DDR4-2666V, PC4-2666V standard. The assembly is SingleRank, comprised of eight Samsung 1Gbx8 DDR4- 2666V SDRAMs. One EEPROM is used for Serial Presence Detect. Both output driver strength and input termination impedance are programmable to maintain signal integrity on the I/O signals in a Fly-by topology.