Quicktime performance Tiger vs Leopard

Discussion in 'macOS' started by huntercr, Nov 19, 2008.

  1. huntercr macrumors 65816

    Jun 6, 2006
    OK... I'm not a conspiracy theorist by any stretch of the imagination, but I've had a chain of events that leave me wondering what's going on:

    First let me tell you my system: Dual G5 1.8GHz 3.5GB RAM.

    Last year I could download and watch 1080i HD quicktime videos ( trailers from Apple's site ) without problems, playing at full resolution with no noticable frame dropping.

    Then after a quicktime update ( don't remember which ), the performance fell down horribly to just a few frames a second for HD movies ( lower res videos still played fine ).
    The next quicktime bumped up the performance back to something reasonable where I could at least "kind of" watch an HD trailer, but still there were sluggish points on most videos.

    So last week I finally pony up for Leopard. Now I can watch 1080i trailers again without any problems and not a single frame drop that I notice.

    What the heck??? Is this because of Leopard supposedly offloading some of the work to the video card? I think I read that it does that right?

    I have actually noticed better performance all around with Leopard but most obvious is the graphics performance ( minimizing windows, dashboard, webpages etc ). I was mad at myself for not upgrading sooner!
  2. wrldwzrd89 macrumors G5


    Jun 6, 2003
    Solon, OH
    Leopard did make some changes to the graphics subsystem in Mac OS X, which are responsible for most of the performance improvements you've noticed. My understanding is that QuickTime itself doesn't offload rendering to the GPU, but Core Graphics, which handles things behind the scenes, DOES in Leopard, and didn't do so in Tiger.
  3. Catfish_Man macrumors 68030


    Sep 13, 2001
    Portland, OR
    CG doesn't offload to the GPU unless it's explicitly enabled in the app. I would suspect this is just due to optimizations in Leopard. As to what caused the slowdown in the first place... no idea :/

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