I have about 850 music files on my PB and just the standard ram, I think 256? Anyway, my friend has a ibook, and she has a lot more music files than I do.. and her laptop is slowing down, lagging some. And she said that it was because of the music files. Is this right? Does large music files have anything to do with lag? I have about 45GB of available space, and my music takes about less than 4GB. Could opening iTunes with all those mp3's lag your computer if you only have 256 ram? Or is there some other technical reasons for it? Thanks!