This 32GB RAM is 100% compatible with Cisco UCS C220 M5.

Information about memory configuration: The following technical specifications should be considered in advance: The device can install 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 expansion is to be carried out 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. The CPU supports 6 DIMMs per memory channel. Maximum memory speed of the possible CPUs: Xeon CPUs of the 1st generation are offered as Bronze, Silver, Gold, or Platinum. The different processor series support different maximum clock frequencies:

Xeon CPU Series max. Speed MHz
Bronze 3100 2133
Silver 4100 2400
Gold 5100 2666
Gold 6100 2666
Platinum 8100 2666.