Ok, this doesn't make any sense. I can have 100% cpu taken up by another program, but as long as I'm in the iTunes window there is no music lag. However, if I go to another window and 50% of the cpu is taken up, the music will start lagging. It's lagging a little bit right now but I have about 80% of my CPU free. Another thing that doesn't make sense is that music that has been ripped from a CD or downloaded from iTunes tends to lag more, but music that has been downloaded (IE a band has a free EP for download, not necessarily illegal but I did download a for sale EP which I already own and deleted it later to test) doesn't. So... what the living heck?