I currently have a macbook pro spring 2010 15 inch entry level (2.4 Ghz i5, 4 gb ram, 320 hdd). I am thinking about selling it and getting a 2011 macbook pro 13 inch mainly for improved portability. Would I really be sacrificing a lot in terms of performance? I mainly use the copy for web surfing, word processing, powerpoint, and basic photo editing. I usually have multiple programs open at once.