I bought my 13" White Macbook in February of 2007. I am almost certain that I maxed out the ram at 2GB when I ordered it. However, in looking up some specs on Wikipedia, I found that my machine, which seems to be designated with the model identifier "MacBook 2,1" in the system profiler, can be upgraded to 4GB with a 3GB barrier. If this is true, I may have some upgrading to do! Is there another number/spec I should check out in the System Profiler to see if I'm eligible for another GB of memory?