For the 667MHz For the 800MHz For the 1066MHz
Click on your machine for correct memory options
Where is this at on my machine? Go to the Apple logo in left corner screen and select about this Mac. Processor Speed and Memory Speed will allow you to choose the correct option for your Mac. Models reporting 667MHz or 800MHz DDR2 are Mac Pro 2006-2008, Models reporting 1066MHZ DDR3
are the 2009 and later.