Why did my MacBook Air get faster with new battery?

Discussion in 'MacBook Air' started by booyahbooyah, Jan 7, 2015.

  1. booyahbooyah, Jan 7, 2015
    Last edited: Jan 7, 2015

    booyahbooyah macrumors regular

    Joined:
    Sep 11, 2011
    #1
    I've been running my MBA (11", mid-2011, Yosemite) with a dead battery for about a month (i.e. always connected to power). I just swapped out the battery with one I got at a value-price off of Amazon.

    The MacBook is now running twice as fast.

    Why?
     
  2. filmbuff macrumors 6502a

    filmbuff

    Joined:
    Jan 5, 2011
    #2
    Because the CPU is throttled when battery voltage is unacceptably low (or the battery is removed)
     
  3. booyahbooyah thread starter macrumors regular

    Joined:
    Sep 11, 2011
    #3
    Interesting. Any good reason idea why?
     
  4. stefanski macrumors member

    stefanski

    Joined:
    Apr 11, 2004
    Location:
    Australia
    #4
    From a no longer existing Apple support document...

    Apple essentially down-clocks the CPU to prevent the system from shutting down if it happens to demand greater power than the AC adapter alone can provide:

    "If the battery is removed, the computer will automatically reduce the processor speed. This prevents the computer from shutting down if it demands more power than the A/C adapter alone can provide."

    If you google it you will find plenty of reports as far back as 2008. It also happens with my MBP from 2009 which I ran for a long time without battery after it blew up. Now, after installing a new battery, it runs noticeably quicker.
     
  5. Newtons Apple macrumors Pentium

    Newtons Apple

    Joined:
    Mar 12, 2014
    Location:
    Jacksonville, Florida
    #5
    That was a good reason and the truth.:rolleyes:
     
  6. John marts macrumors member

    Joined:
    Sep 20, 2014
    #6
    I've noticed my computer is a little sluggish at under 10% battery. I guess this is for the same reason?
     
  7. satinsilverem2 macrumors 6502

    satinsilverem2

    Joined:
    Nov 12, 2013
    Location:
    Richmond, VA
    #7
    I ran my 2011 Macbook Pro without a battery for around 2 months and noticed a severe cut in processing power. I think OS X automatically down clocks to half speed or to 1GHz depending on model. From what I was seeing my 2.7GHz i7 wouldn't go above 1GHz.
     
  8. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #8
    You can search for "Intel Power Gadget" and install that and it will tell you what frequency your CPU is running at, plus how much power it's drawing and what its temperature is, FYI.
     

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