Observations: Recently, not sure when it happened, with upgrade to Lion or before, but I have not been able to cleanly watch a video of any type in iTunes while something [movie, tv show, app, podcast, etc.] is downloading from the iTunes store. This is particularly annoying when renting a movie, and trying to start watching before the movie is downloaded. There have been no hardware changes, and playback used to work perfectly during download. There have been a lot of recent changes to iTunes, Mac OS, and I would like to fault isolate. How can I determine which software might be causing this problem, or if something is interfering with playback?

Problem: iTunes video playback is choppy only while downloading anything from the iTunes store. Video is choppy at all sizes, e.g. actual size, full screen.

System Setup: iMac 20-inch, Early 2008, 2.4GHz Core 2 Duo, 4 GB 800 MHz DDR2 SDRAM, ATI Radeon HD 2400 XT 128 MB, Mac OS X Lion 10.7.2; iTunes 10.5.2; iTunes library stored on external Firewire HDD, HDD approx. 50% full; All software up to date.

Solutions already tried: iTunes reinstalled; Quicktime reinstalled; reboot; All other apps closed; iDevices ejected from iTunes panel;

  • This almost sounds like a lack of CPU power, but that Mac should have plenty of power to playback video. I would look at Activity Monitor while you are trying to play a video and look at the CPU use while playing back a video. Jan 15, 2012 at 21:55
  • CPU was interesting, it varied widely from 1% to 122%, but mostly stayed around 10% of 1 CPU. I would expect the CPU to be higher and more steady state. There was plenty of SDRAM free, iTunes Real+Virtual Memory was below 1GB. Also, the video being played was previously downloaded.
    – Matthew
    Jan 16, 2012 at 9:24

1 Answer 1


I'm not sure how this was resolved, but the latest version of iTunes now works fine.

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