I just received my maxed out 21.5" iMac and am having significant performance issues with iTunes. Photoshop, Lightroom, etc. are lightning fast but iTunes beachballs constantly and occasionally freezes. A simple scrolling through my music or movies takes forever. Using the search function will usually freeze iTunes for several seconds while typing. The only thing i can think of is that my media lives on a networked Drobo. But my MacBook Pro has the same set up with zero performance issues (both wireless). Also, I don't have it configured to copy the media locally. Any thoughts?