I was wondering if there is a noticeable difference in playback when all my content is on an external hard drive, like a noticeable difference between a USB or FireWire hard drive. I know that FireWire is obviously faster, but does that apply when it's playing content in Plex, or does the RPM matter more. I have a Mac Mini with a external hard drive for Plex and iTunes. All of my iTunes music and all my movies are on the hard drive. I have a Macbook and Macbook Pro that are set to read the hard drive for their iTunes library wirelessly. When I'm away with wifi I use either Simplify Media or BackToMyMac to play back music.