This 32GB RAM is 100% compatible with Cisco UCS C220 M3. Information on memory configuration: The following technical specifications should be considered in advance: RDIMM (Registered DIMM) or LRDIMM (Load Reduced DIMM) RAM can be installed in the device. LRDIMM memory is recommended when large memory capacities are required. RDIMM memory modules cannot be mixed with LRDIMM memory. If a memory upgrade is to be made with the existing RAM, it must be checked which memory technology (RDIMM / LRDIMM) is present. Memory slots without a processor must not be populated. A higher memory clock speed of the memory module will automatically adjust to the clock speed specified by the system. This can especially be the case with larger capacities. Low Voltage memory with 1.35V will be clocked at 1.5V when mixed with 1.5V memory through the fallback option present in the memory.