My Macbook Pro running Mountain Lion slows down dramatically when the battery is below 4-5%. All the applications running are very slow to respond, and several have the "Application not responding" message when I right-click on them in the dock. Now everything works fine when the battery is above 5%, so I'm wondering what goes on when the battery is low that causes the performance drag. Basically, I have two questions:

  1. What is causing this lag (for the sake of curiosity)?
  2. How can I fix it (for the sake of practicality)?

System Info:

  • Device: Macbook Pro (Spring 2012) 13-Inch running Mountain Lion (10.8)
  • Memory: 8GB
  • Processor: 2.8 GHz Intel Core i7
  • Storage: 500GB SSD Drive with more than half free
  • 2
    It sounds like CPU speed stepping to me.
    – ephsmith
    Aug 19, 2012 at 23:16
  • 1
    has the provided answer solved your problem? Because I don't see any of the described settings in 10.8
    – barbaz
    May 1, 2013 at 8:56
  • 1
    @barbaz - It didn't really solve the problem, but it seems like there is no solution so I accepted it.
    – pasawaya
    May 1, 2013 at 12:06
  • Same problem with MacBook Air 2013.
    – KPM
    Nov 20, 2014 at 12:47
  • 1
    I'd really like to find a solution to this, it's annoying for me as I can't do any work with the last 10% of battery life, so it's effectively dead anyway.
    – Tom
    Jul 29, 2015 at 8:22

2 Answers 2


See if this link provides you with some useful knowledge. http://smallbusiness.chron.com/change-processor-speed-macbook-pro-43635.html

It's likely that the MBP is automatically scaling the processing power back to conserve battery power, but that isn't necessarily the only cause.


This is normal, the same thing happens on my MacBook Air (11 inch, 2014) when the battery gets around 5%, performance drops significantly, it does this because your battery level is so low, just plug it in a charger and it will start working normally again. If this doesn't solve it, try resetting the SMC.

  • 3
    Soooo is there a command I can run or a kernel change I can make to prevent this??
    – s g
    Jul 9, 2016 at 0:44

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