Amazon.com: OWC 16GB (2 x 8GB) PC8500 DDR3 ECC-R 1066MHz DIMMs Memory Compatible with Mac Pro Early 2009 & Late 2010 'Nehalem' & 'Westmere' Systems and Early 2009 Xserve. (OWC85MP3S8M16GK) : Everything Else
16GB (2 X 8GB) DDR3 1066MHz PC3-8500 240-pin Memory RAM DIMM for Desktop by NEMIX RAM at Amazon.com
Corsair CMSA4GX3M1A1066C7 Apple Certified 4GB (1x4GB) DDR3 1066 MHz (PC3 8500) Laptop Memory 1.5V at Amazon.com