Making Sure Your MacBook Recognizes the New Memory
After installing additional memory in your MacBook, check whether the computer
recognizes the new memory.
To check the computer’s memory:
Start up your MacBook.
When you see the Mac OS X desktop, choose Apple () > About This Mac.
For a detailed breakdown of the memory installed in your computer, open System
Profiler by clicking More Info, and then click Memory.
If your MacBook doesn’t recognize the memory or doesn’t start up correctly,
confirm that the memory you installed is compatible with your MacBook and that
it’s installed correctly.