Gigaram 3GB (3x1GB) DDR3-1066 ECC DIMM for Apple Mac Pro 8-Core 2.60Ghz Intel Xeon "Nehalem" (Apple# 3 x MB980G/A) 1GB PC3-8500, DDR3-1066, 1066Mhz, 8.5GB/s Bandwidth, CAS 7-7-7-20, 5ns Cycle Time, ECC, Dual Rank, RoHS Certified, 256x72, 1.5V, 240pin DIMM This DIMM module is specifically designed and SPD configured for the "Nehalem" Mac Pro. This part will match up with the original 3GB or 6GB that came with your machine to bring you up to 4GB or 8GB. This DIMM includes the Apple Specified Thermal EPROM Sensor. This module is compatible with the latest Apple Firmware