I have a 2gb macbook pro and want to upgrade to 4gb. I've read other similar posts but i dont see one that addresses my question. My MBP comes with (2) 1gb sticks of RAM. If i want to upgrade to 4gb, does it matter if i get a single 2gb stick added on or should i get (2) 1gb sticks like the original setup. Does it matter? Not sure how many slots there are. Perhaps i should just get (2) 2gb and replace the old ones altogether.