Thinking of doing the above to my parents machine. It has been quite slow for some time. It has its good moments but overall very slow at opening anything. I wondered if a clean install would help out, but I'm not sure about replacing the files like the Photos library and keychains etc if I do this. I have a Time Machine backup, but I don't know the steps to replace only certain things like this. From Crucial up to 16GB is supported. For parents its going to be typing documents, emails, internet, some photos, iTunes and iPhone/iPod management, I can't think of much more. Is 16GB overkill or for the price is it worth doing anyway. It currently has 4GB The SSD will make a big difference anyway I'm sure, but don't want to spend unnecessarily.