This 32GB RAM is 100% compatible with Dell PowerEdge R660xs.

Information on memory configuration: The following technical specifications should be considered in advance: The device can be equipped with RDIMM and RDIMM 3DS (Registered DIMM) or LRDIMM and LRDIMM 3DS (Load Reduced DIMM) RAM. LRDIMM memory is recommended for achieving large memory capacities. RDIMM and RDIMM 3DS memory modules cannot be mixed with LRDIMM and LRDIMM 3DS memory. If a memory upgrade is to be made with the existing RAM, it must be checked which base memory technology (RDIMM / LRDIMM) is present. Memory slots without a processor should not be populated. A higher memory clock of the memory module will automatically adjust to the memory clock specified by the system. This can especially be the case with larger capacities.