DDR2-667Mhz vs. DDR2-800Mhz

 

To find out which MacBook 5,2 version you have:

about this mac Select "About This Mac" in your Apple Menu.
667 mhz 667 Mhz means you have the MacBook 5,2 667Mhz version.
800 mhz 800 Mhz means you have the MacBook 5,2 800Mhz version.