CT2K16G3ERSLD4160B is a 32GB kit consisting of (2) 16GB Dual Rank DDR3 Server modules that operates at speeds up to 1600 MT/s and has a CL11 latency. It is Registered with ECC Error Correction. It conforms to the industry standard RDIMM layout of 240 pins and runs at 1.35v. This is not standard desktop RAM, these modules are meant for servers that require DDR3, ECC, Registered memory. Please check for compatibility with your system before purchase – memory selector tools available at crucial.com. Note: You cannot mix registered memory with unbuffered memory within the same system.