Mac Pro supports up to 12 DIMMs installed in configurations of 4, 6, 8, or 12 DIMMs.
High performance multi-channel memory,
Install in pairs for best performance..
Backed by an OWC Limited Lifetime Warranty.
Mac Pro can use either RDIMM or LRDIMM, but they cannot be combined. Additionally, LRDIMM modules must all be of the same size. Configurations of 5, 7, 9, 10, and 11 DIMMs are not supported. Other configurations of 1, 2, and 3 DIMMs are for diagnostic use only.