This 32GB memory is 100% compatible with QNAP TS-h686. The following technical specifications should be considered in advance: ECC DIMM (with Error Correction Code) or RDIMM (Registered DIMM) RAM memory can be installed in the unit. RDIMM memories are recommended if large memory capacities are to be achieved. The different memory technologies (ECC/RDIMM) must not be operated in mixed mode. If a memory expansion is to be carried out with the already existing RAM memories, it must be checked which memory technology (ECC/RDIMM) is available. Mixed equipping with different capacities is not possible!.