This 32GB RAM is 100% compatible with the ASRock Rack SP2C621D16-2T.

Information on memory configuration: The following technical specifications should be considered in advance: The device can accommodate 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. When using a multiprocessor system, the memory slots should always be populated identically for each CPU. Memory slots without a processor should 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.