Apple 14DDR3X1664R 64.0GB (4 x 16GB) Factory... at MacSales.com
IBM 64GB (8 x 8GB) DDR3-1333 MHz PC3L-10600R ECC– Cloud Ninjas
OWC 64GB (4 x 16GB) PC10600 DDR3 ECC-R 1333MHz DIMMs Memory Compatible with Mac Pro Early 2009 & Late 2010 'Nehalem' & 'Westmere' Systems and Early 2009 Xserve. (OWC85MP3S9M064K) at Amazon.com
Black Diamond Memory-Black Diamond Memory
Kingston Technology Value RAM 64GB Kit 1600MHz DDR3 ECC CL11 DIMM DR x 4 with TS Intel Desktop Memory at Amazon.com
OWC 64.0GB (4X 16GB) PC10600 DDR3 ECC-Registered 1333MHz 240 Pin Memory Upgrade Compatible with Select 2009-2012 Mac Pro Models (OWC1333D3X9M064) at Amazon.com
64GB PC3-12800L 8 Ranked DDR3 Load Reduced 1600Hz ECC Registered Memory // STI Kansas City