Disc spins faster on battery power

Discussion in 'MacBook Pro' started by Clete2, Jul 21, 2010.

  1. Clete2 macrumors 65816

    Clete2

    Joined:
    Sep 20, 2008
    Location:
    USA
    #1
    I'm watching a DVD on my MBP (April 2010) and I've noticed that as soon as I unplug the MBP, the disc spins faster. When I plug it back in, it slows down again.

    Why?
     
  2. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #2
    Just a guess here but, could it be caching it for playback?
     
  3. Clete2 thread starter macrumors 65816

    Clete2

    Joined:
    Sep 20, 2008
    Location:
    USA
    #3
    That's my guess, but it doesn't really stop spinning quickly, unless I didn't wait long enough..
     
  4. Clete2 thread starter macrumors 65816

    Clete2

    Joined:
    Sep 20, 2008
    Location:
    USA
    #4
    Hey, you're right. I kept it unplugged for ~5 minutes and it spun down.

    "Playing DVDs on a portable computer
    If your portable computer has a DVD drive or is connected to an external DVD drive, you can use DVD Player to play DVDs on your portable computer. To preserve battery charge when you’re not connected to a power supply, DVD Player loads a portion of the movie into your computer’s cache to play the movie and then puts the DVD drive to sleep. When DVD Player needs to load more of the movie into the cache, it wakes the drive. Typically you are unaware of this behavior. But if you scan ahead to a portion of the movie that is not yet cached in memory, it might take several seconds for the DVD drive to wake.

    The DVD Player preference that puts the DVD drive to sleep when a movie is playing is set by default. To turn it off, choose DVD Player > Preferences, click Player, and then deselect the “Put the DVD drive to sleep” checkbox."

    It would be cool if it would cache even when plugged in so the disc will spin down..
     
  5. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #5
    That's pretty neat. I know my (very) old Windows laptop did that with music cds.
     
  6. Clete2 thread starter macrumors 65816

    Clete2

    Joined:
    Sep 20, 2008
    Location:
    USA
    #6
    Yeah. My CD player used to have that 60-second skip protection. LOL
     

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