I've participated in several threads identifying performance problems and wanted to see if we could note performance problems in one thread. Not setup problems, but glitchy UI, movies pausing, content disappearing and reappearing etc. I'm not sure how common the problems I've experienced are. So far I have identified the following causes of performace problems: Glitchy UI and TV reboots/long pauses - With my Sony 46" LCD and using HDMI I have experienced TV reboots, long lock-ups when switching selecting that input, and very patchy UI response times. When using Component input these problems completely go away. Video playback pausing, locking up and streaming library content showing as not available randomly during playback of streamed content - iTunes 7.6.1 is causing this. I've found the only way to clear this up for a few days is to reboot my Mac Mini Core 2 Duo. Just killing iTunes and restarting the app doesn't seem to clear it up as well.