Apple MacBook (13-inch, Aluminum, Late 2008) - Manual (Page 49)

Chapter 3 Boost Your MacBook 49
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:
1 Start up your MacBook.
2 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 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 is installed
correctly.