OWC 32GB (2X 16GB) 1866MHz PC3-14900 DDR3 ECC-R SDRAM Memory Upgrade Kit, ECC Registered Compatible with Mac Pro 2013 (OWC1866D3R9M32) : Everything Else

Your Mac Pro can use ECC Unbuffered or ECC Registered Memory, but they cannot be combined. Please remove all Unbuffered Memory when installing these

OWC 8GB DDR3 ECC Registered CL9 PC3-14900 1866MHz CL13 SDRAM Memory Ram Upgrade Module Compatible with 2013 Mac Pro Models (OWC1866D3MPE8GB)

OWC 16GB (2x8GB) DDR3 ECC Unbuffered CL13 PC3-14900 1866MHz SDRAM Memory Ram Upgrade Module Compatible with 2013 Mac Pro Models (OWC1866D3E8M16) : Everything Else

2013 Apple Mac Pro 64GB Memory Upgrade Kit From OWC

A-Tech 16GB RAM for Apple Mac Pro Late 2013 DDR3 1866MHz PC3-14900R ECC RDIMM 2Rx4 1.5V 240-Pin Registered DIMM Memory Upgrade at

OWC 32GB (4 x 8GB) PC14900 DDR3 1866MHz SO-DIMMs Memory RAM Upgrade Compatible with 2015 (Late) iMac 27 w/Retina 5K Models and Compatible PCs (OWC1867DDR3S32S) at

OWC 16GB PC14900 DDR3 1866MHz SO-DIMM Memory RAM Upgrade Compatible with 2015 (Late) iMac 27 w/Retina 5K Models and Compatible PCs (OWC1867DDR3S16G) at

32GB OWC Memory Module (1 x 32GB) 1333MHz PC3-10600 DDR3 ECC-R SDRAM

OWC 32GB (2X 16GB) 1866MHz PC3-14900 DDR3 ECC-R SDRAM Memory Upgrade Kit, ECC Registered Compatible with Mac Pro 2013 (OWC1866D3R9M32) : Everything Else