I have a 2010 2.8GHz Quad Mac Pro. I understand that it can use both 1067MHz and 1333MHz RAM sticks, but that it will only run at 1067MHz regardless. However, I think I read somewhere that if I upgrade the CPU to a 6-core 3.33 W3680, then the computer will be able to run the RAM at 1333MHz. Is this correct? If so, then I should probably order 1333MHz ram instead of 1067MHz in order to be ready if I decide to upgrade the CPU in the future.