64GB (16GBx4) DDR3 ECC 1866MHz SDRAM for the 2013 Mac Pro Model 6,1. Contains two (2) 8GB DRAM memory modules that are specifically designed and SPD configured for the 2013 Mac Pro Model. These ECC DIMMs contain the Apple Specified Thermal EPROM Sensor.
Specifications:The following installation video covers the Mac Pro DDR3-1866Mhz.
Click here to find Apple's installation guide for the 2013 Mac Pro.