I just received my new 24" iMac 3.06Ghz. I purchased 2x2GB (4GB RAM) online but it will only arrive on friday. I have already setup my computer. My question is, for an optimum performance, should I reinstall the entire OS after installing my new RAM? I know I don't need to reinstall everything, I have always upgraded my own RAM but in terms of making the computer faster, should I reinstall the whole thing? Thanks in advance.