I have updated my mac from 10.8 (Mountain Lion) to 10.9 (Mavericks) and after the successful update my mac just extremely slowed down. In the Activity Monitor I saw the “kernal_task” is using over 600% of CPU!
I google and found something helpful in rdoxenham.com. Now I am writing a summary of it for you if you are having the same type of problem just use it.
I take absolutely no responsibility for any damage or loss caused to you or your property, you do this of your own free will
Open terminal and type:
system_profiler -detailLevel mini | grep "Model Identifier:"
You can see the model identifier for you mac. Like:
Model Identifier: MacBookPro8,2
In this case, your model identifier is: MacBookPro8_2
Right click in finder and select “Go to folder” and go to
You can see some .plist files. Find one with your model identifire like: MacBookPro8_2.plist
Rename it like MacBookPro8_2_old.plist
And you are done.
NB: This solution also works fine for 10.8 and 10.7
Enjoy the speed!