OWC 64.0GB (8 x 8GB) DDR3 ECC-R PC10600 1333MHz SDRAM ECC For Mac Pro Memory Upgrade Kit For Mac Pro 2009-2012 'Nehalem' & 'Westmere' models and PC desktops with Intel / AMD---May Not be mixed with other modules 8 x 8GB (64GB) OWC Brand PC10600 DDR3 ECC-R 1333 MHz 240 pin DIMM 1.5V Mac Pro Memory Upgrade Kit Matched pair, perfect for the Mac Pro 8-core / Quad-core Xeon systems! Compatible: Mac Pro 12-Core (Model ID:MacPro5,1) Mac Pro 8-Core (Model ID:MacPro5,1) Mac Pro 8-Core (Model ID:MacPro4,1) OWC Memory Lifetime Limited Warranty including Advanced Replacement Program Mac Pro 12-Core (Mid 2010-2012) (July, 2010/June 2012) Model ID: MacPro5,1 (2.40GHz, 2.66GHz, 2.93GHz, 3.06GHz) Mac Pro 8-Core (Mid 2010) (July, 2010) Model ID: MacPro5,1 (2.4GHz) Mac Pro (Early 2009 8-Core)(March, 2009) Model ID: MacPro4,1 (2.26GHz, 2.66GHz, 2.93GHz) PC Desktops:Compatible with Intel / AMD Process based PCs capable with the specifications listed above.