CT4K16G4DFD8266 is a 64GB Kit consisting of (4) 16GB DDR4 desktop modules that operates at speeds up to 2666 MT/s and has a CL19 latency. It is an Buffered DIMM. It conforms to the industry standard DDR4 ECC UDIMM layout of 288 pins and is compatible with systems that take DDR4 2666MT/s UDIMM memory.