OWC 32GB (2 x 16GB) PC10600 DDR3 ECC-R 1333MHz DIMMs Memory Compatible with Mac Pro Early 2009 & Late 2010 'Nehalem' & 'Westmere' Systems and Early 2009 Xserve. (OWC85MP3S9M032K) at Amazon.com
OWC 4.0GB PC14900 DDR3 1866MHz ECC Memory Module at MacSales.com
HP 2GB (1x2GB) DDR3-1600 MHz ECC RAM at Amazon.com