I have a 2009 Macbook Pro, 4GB RAM, 2.26GHz Intel Core 2 Duo. Check battery warning but nothing else overtly wrong.

Since I updated to Mavericks (from Snow Leopard), it has been running incredibly slowly and the fan has been spinning up constantly. Icons bouncing for a long time in the dock before launching (especially Skype), really slow to type in the new Pages (old one is fine), etc., despite Activity Monitor showing low or medium memory pressure and the CPU being at relatively low usage.

Resetting the SMC brings it back to the speed it used to be at, but after a couple of hours of usage, my MacBook has slowed to a crawl again and the only thing that will speed it up again is another SMC reset.

Any ideas?

  • did you erase and install when in upgraded to Mavericks?
    – dwightk
    Apr 24, 2014 at 14:22
  • No, just installed via AppStore
    – Tim
    Apr 24, 2014 at 20:21

2 Answers 2


It is good you mentioned the Check Battery Warning since that is your problem.

Mac will cut down the CPU speed to 1/2 if the battery is not up to snuff.

Your SMC reset will ratify the issue for a while, but since the battery is on the verge, it will eventually trigger the cutting the CPU Speed/Power consumption to 1/2 of normal. You see that as computer slowdown.

If you want to verify my claim there is a CPU test made by Intel to check the CPU and do that during the slow times as comparison to when it is fast.

Download it, and yes you can keep it :)

Here is a sample what it looks like on my MBA.

Intel CPU

  • Excellent, thanks for the help. Is there any way to reset the service battery? I have 906 cycles on it but I'm still getting good life and don't have time to go to the Apple Store (it's exam season for me right now).
    – Tim
    Apr 24, 2014 at 20:23
  • Please ask that as new question so we do not mess this one up, if we are done here.
    – Ruskes
    Apr 24, 2014 at 20:33
  • @Buscar웃 Do you know of such a monitor application that will work on a Intel Core 2 Duo P8800? If I try the linked app it tells me I don't have a 2nd gen Intel Core processor. Apr 25, 2014 at 2:10
  • @BartArondson sorry I do not.
    – Ruskes
    Apr 25, 2014 at 14:42

If you fix the battery issue and still have performance problems, you could try the solution I found. I had a MacBook Pro that ran dog slow and the problem didn't go away after a reformat and reinstall and a battery replacement. It stemmed from a runaway kernel_task process that you could see in Activity Monitor was using 150% CPU.

After several bouts with the machine over several months, I finally properly tuned my google-fu and found some answers at http://www.rdoxenham.com/?p=259

If your kernel_task is doing the same thing, try this...

Effectively, you just remove your "Model Identifier" .plist file from a package within a package at:


• You can find the model of your computer: Apple Menu -> About This Mac -> More Info... -> System Report

(or by running system_profiler -detailLevel mini | grep "Model Identifier:" in terminal)

• You can enter a package's content by right clicking it. You'll have to do this twice to get to where you're going.

Keep in mind that you may at this point need to be very careful about making sure you don't overheat your laptop by somehow defeating its ventilation or heat dissipation.

If it doesn't fix your problem, just replace the model.plist.

  • Good answer for major surgery! how does one replace the model.plist ?
    – Ruskes
    Apr 29, 2014 at 9:59

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