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
Amazon.com: CMS 32GB (4X8GB) DDR3 10600 1333MHZ ECC Registered DIMM Memory Ram Upgrade Compatible with Dell® Poweredge T610 Ddr3 Ecc Reg for Server Only - B103 : Electronics
OWC 32GB (4 x 8GB) PC3-10600 DDR3 ECC-R 1333MHz... at MacSales.com
32GB (4x8GB) DDR3-1600MHz PC3-12800 ECC UDIMM 2Rx8 1.35V Unbuffered Server Memory by NEMIX RAM at Amazon.com