Today I upgraded my macbook from 2 GB to 3 GB. I am wondering whether I should eventually change out the other 1 GB memory stick for another 2 GB one. My macbook is from mid 2007 and can only recognize up to 3.3 GB. So, is it worth it? Is it that much of a difference, or should I just save my money and stick with the 3 GB I have now?