Is this a video\graphics glitch on the MBP or is it just me?

Discussion in 'Mac Pro' started by bella92108, Apr 7, 2006.

  1. bella92108 macrumors 68000

    Joined:
    Mar 1, 2006
    #1
    I have been keeping up to date with all the software revisions and what not, here's my issue...

    When I'm watching a video or on a webpage of a video that's either being streamed or on my hard drive (rules out web issue) when the window is not selected as on top of the other apps, the video gets choppy, real choppy.

    Where I notice this is if I'm watching a DVD or playing a Quicktime Video off my hard drive and I open my ADIUM app, when I am sending an IM (the top window on the screen is Adium rather than Quicktime), the video get's choppy. I also just noticed it when I was on myspace, one of the advertisements was an animated image and when I switched to an instant message window, the ad got all jerky rather than the smooth flow it was before...

    Anyone know if this can be remedied?

    Thanks!
     
  2. CubeHacker macrumors 65816

    CubeHacker

    Joined:
    Apr 22, 2003
    #2
    It seems you're describing two things here - one which i'm familiar with and another which i'm not.

    Yes, Safari always seems to automatically lower its allocated CPU usage when its not in the front window. I'm not sure why it does this (perhaps to hide the G4's slow speeds), but if Safari isn't in the front window and active, then it uses very little CPU and slows down things like movies and flash animations playing in Safari. This is normal, and Safari has always done this. Perhaps we should write to Apple to disable this "feature" now that most new macs are shipping with dual processors and can easily handle the load.

    As for DVD player and quicktime, that shouldn't be happening. Even my ancient G4 can play a movie in the background without stuttering.
     
  3. spencecb macrumors 6502a

    spencecb

    Joined:
    Nov 20, 2003
    #3
    This is not a feature to "hide" the "slow" speeds of the G4. It is called pre-emtive multi tasking, and is one of the greatest features of OS X, as it empliments this feature very well. This is to ensure that whatever program that you appear to need the most CPU time for is given that by OS X, while cutting back on CPU time for other applications.
     
  4. CubeHacker macrumors 65816

    CubeHacker

    Joined:
    Apr 22, 2003
    #4
    No, not really. While yes, OSX is a preemptive multitasking OS, what you described (the OS allocating CPU cycles to different programs) is not what Safari is doing. Basically, Safari is slowing itself down when its not the top window - whether something else is running in the background or not. Even if Safari is the only app open, and you switch to the finder, Safari will suddenly cut almost all CPU usage. This is NOT what preemptive multitasking is about, and the only logical reason for Safari doing this is because of speed concerns. Windows is able to run any browser at full speed whether its the active app or not without slowdown. I believe Camino and Firefox also work this way under OSX.
     
  5. spencecb macrumors 6502a

    spencecb

    Joined:
    Nov 20, 2003
    #5
    I'm not sure if that is correct either. It sure as hell seems to me that OS X would drop the CPU usuage from Safari when you switch over to the Finder (or any other application). That surely sounds like preemptive multitasking to me.

    And how much CPU time is your copy of Safari taking up, anyway? Mine rarely uses more than about 5-10% maximum, and while idle (even while it is the front window) it uses about .30%.
     
  6. CubeHacker macrumors 65816

    CubeHacker

    Joined:
    Apr 22, 2003
    #6

    Safari should not drop CPU usage if no other app needs it. So basically, if you only have Safari open with a flash video playing (which usually takes up most of the CPU), and then switch over to the finder, Safari should continue to use up as much CPU as it needs, until something else needs CPU, and then the OS "shares" the CPU between the two apps. THAT is the point of pre-emptive multitasking. Instead, Safari is dropping CPU usage no matter what as soon as its no longer the active window.
     
  7. crazzyeddie macrumors 68030

    crazzyeddie

    Joined:
    Dec 7, 2002
    Location:
    Florida, USA
    #7
    DOACleric is right on this one. Safari has some sort of programming that automatically makes it lower CPU usage in the background. Just because you switch to the Finder does not mean that the Finder magically takes over the rest of your CPU time. The reason OS X is better than OS 9 is because it allows for apps to run as fast as they need to, whether in the foreground or background, as long as you have the total CPU capacity necessary. For some reason Safari doesn't honor this. Very annoying for me, personally, when I have a dual processor machine and Safari makes everything look crappy for no reason.

    Anyway, back to the original question, it is normal for Safari. It is not normal for Quicktime or DVD Player. You should make sure that the video isn't just getting choppy when you open Adium, as that might take up most of your CPU (but it doesn't on my MBP). If you're just typing a message, it should take very little CPU, 5% max after you account for spell checking and Adium sending the "user is typing" message to your buddy.
     

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