I bought a MBP 15" (the I5 2.4ghz model) and after messing around with it today, i realized that my new 15" isn't as responsive - or at least feel fast - as the 13MBP (core2duo 2.4ghz model). is there a technical reason why i feel this way about the 15"? is it because the screen is bigger? i post this question bc i thought the 15inch would definitely perform a lot better than the 13inch model given the new updated specs. hmm... is there something wrong with my new 15"MBP? thanks.