This 128GB memory is 100% compatible with ASRock Fatal1ty X99M Killer.

Memory for Core i7 5th Generation CPU: Optimal performance is achieved by using 4 or 8 identical memory modules per CPU. If an i7 processor is used, UDIMM memory modules must be installed.

Memory for Xeon CPU: When using a Xeon CPU, ECC and RDIMM memory must be used. ECC DIMM (with error correction code) or RDIMM (Registered DIMM) RAM memory can be installed in the unit. RDIMM memories are recommended when large memory capacities are to be achieved. The different memory technologies (ECC/RDIMM) must not be mixed. If a memory expansion is to be made with the already existing RAM memories, it must be checked which memory technology (ECC/RDIMM) is available.

CPU in the system:

• UDIMM
• UDIMM ECC
• RDIMM

Which memory technology can be used, depending on the CPU Core i... The memory technology that can be used depends on the CPU:

Core i7-5960X: 4GB UDIMM, 8GB UDIMM, 16GB UDIMM, 32GB UDIMM
Core i7-5930K: 4GB UDIMM, 8GB UDIMM, 16GB UDIMM, 32GB UDIMM
Core i7-5820K: 4GB UDIMM, 8GB UDIMM, 16GB UDIMM, 32GB UDIMM
Xeon E5-1600 v3: 8GB UDIMM ECC, 8GB RDIMM, 16GB RDIMM, 32GB RDIMM, 64GB RDIMM, DDP
Xeon E5-2600 v3: 8GB UDIMM ECC, 8GB RDIMM, 16GB RDIMM, 32GB RDIMM, 64GB RDIMM, DDP, 128GB RDIMM 3DS, 256GB RDIMM 3DS.