Less power using battery?

Discussion in 'MacBook Pro' started by Arkanok, Jul 9, 2007.

  1. Arkanok macrumors 6502a


    Feb 13, 2007
    I was using my sr-mbp on the battery today, and when i used the expose and or the dashboard, i noticed that it didnt run as smoothly as it does when its plugged into the wall. Is this normal?
  2. kolax macrumors G3

    Mar 20, 2007
    Yes - the CPU and GPU don't get used at their full potential when on battery to preserve battery life.
  3. Arkanok thread starter macrumors 6502a


    Feb 13, 2007
    Is there a way to enable their full potential if i wanted to? (yea i know it would kill the battery a lot lol, and this is my first mac so i'm still learning)
  4. hsotnicaM macrumors regular

    Jun 19, 2007
    There are three settings - Better Battery Life, Normal, Better Performance. What the real world difference is I don't know.
  5. iBookG4user macrumors 604


    Jun 27, 2006
    Seattle, WA
    Better performance makes it less likely for the CPU and GPU to scale back clock speed to preserve battery life. Better battery life makes it more likely for the CPU and GPU to scale back clock speed to preserve battery life. Normal is a balance between them.
  6. Sbrocket macrumors 65816


    Jun 3, 2007
    The Power Management settings that you refer to do not affect processor throttling on Intel processors; that is an artifact left over from the age of PPC Macs. The settings you refer to (Better Performance, Normal, Better Battery Life) now only adjust the time until screen sleep or computer sleep that you can adjust to your own custom settings. If they actually did affect processor frequencies, then what does "Custom" equate to in terms of performance? It doesn't make sense.

    As far as I know, neither of your cores' operating frequencies are reduced when you switch from AC power to battery power. The Processor control panel that is part of the CHUD Developer tools shows that both cores are operating at 2.40 GHz whether my SR MBP is plugged in or working on battery. The only thing I can think of is that the frequency might be reduced when your battery starts to run low (?), but I haven't tested it myself.

    Without any hard proof on either side (I can't prove that it isn't slowing down, but you can't show that it is), I'm tempted to say its just a placebo effect and that your computer either isn't slowing down or is slowing down for some unrelated reason.
  7. Arkanok thread starter macrumors 6502a


    Feb 13, 2007
    Hmm, you may be right but still, if its unplugged with full battery or low battery, it still seems to run a little less smoothly for the expose/dashboard features. However, i tested running World of Warcraft while purely on battery power and it seems as if it ran just as well as it does on AC power. So i think the cores maybe slow down for general os use, but when needed (HD quicktime file, or games) maybe thats when it runs back to normal? Just a hunch maybe. Any thoughts?
  8. beginner0 macrumors member

    Jan 23, 2007
    It is possible (in general) that the CPU slows down a bit when not needed, and speeds up when needed. This is true for my old (non mac) laptop, with NHC for monitoring.

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