This 128GB RAM is 100% compatible with ASRock TR-KNL.

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. A higher memory clock of the memory module automatically adjusts to the memory clock set by the system. This can especially be the case with larger capacities.