How to Determine the Exact Model of Your MacBook
Most folks know the type and model of their computers, but there’s a catch here, too: Sometimes the memory that you need varies by the processor in your MacBook. Your eye should be on the actual processor speed and bus speed — the transfer speed that data reaches whilst speeding across your motherboard — because they’re the identifying factors here.
Your salvation turns out to be the About This Mac dialog. Just click the Overview toolbar button to display both the machine speed (or processor speed) and the common identifier that Apple uses to refer to your specific model. Grab a piece of paper (or open a Sticky) and add these two figures.
Now you’re armed with the information that you need to go online and buy the right memory. Or, if you’d rather work directly with a human being, you can visit your local Apple dealer, present that most august personage with the list, and have the memory upgrade ordered for you.
Buying memory online is much cheaper. Try the following online stores: