This 128GB RAM is 100% compatible with the Dell PowerEdge XR11. Information on memory configuration: The following technical specifications should be considered in advance: The device can have RDIMM and RDIMM 3DS (Registered DIMM) or LRDIMM and LRDIMM 3DS (Load Reduced DIMM) RAM installed. LRDIMM memory is recommended when large memory capacities are required. 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. When using a multiprocessor system, the memory slots should always be populated identically for each CPU. Memory slots without a processor must not be populated. If memory modules with higher clock rates than specified by the system are offered, the memory clock will automatically adjust to the system specifications.