64GB Total memory using 4pc of 16GB DDR4, 2666MHz, Non-ECC, CL19, 2R, X8, 1.2V, Unbuffered, DIMM, 288-pin Max Capacity: 128GB Sockets: 4 Compatible with: ASRock Motherboard B360 Pro4, B360M Pro4, B365 Phantom Gaming 4, B365 Por4, B365M Phantom Gaming 4 Lifetime exchange or repair warranty against manufacturing defects by Computer Memory Solutions. Manufactured by Computer Memory Solutions. We don't use OEM or Generic Modules to avoid incompatibility. In most cases, you can mix manufacturer parts, however, all memory in the system will run at the slowest performance of the installed modules or CPU/processor capability. To maximize performance, we recommend that you install your memory modules in matched pairs. A 64-bit Operating System is required to utilize more than 4GB of memory.