56GB (3x16GB)+(1x8GB) Memory Ram Apple Mac Pro 5.1 2010 Quad/Hex Core all CPUs
Your Mac Pro has 4 slots and the maximum possible upgrade is 56GB (3x16GB + 1x8GB) or 64GB (4x16GB) depending on what CPU you have installed . Kit Capacity: 56GB. Quad Core Model: 2.80Ghz and 3.20Ghz.