Energy impact of Safari is extremely high on my Macbook Air Mid 2013 El Captian 10.11.2. It lead to high usage of CPU (Temperature ~65.0°C) and the CPU fan is running in full speed (6500.0 RPM) constantly.

I have tried so far:

  1. Clear all Safari cached
  2. Restart laptop
  3. Remove/disable all extensions
  4. Uninstall all the software that might possibly affecting e.g. Anti-Virus

The issue is only happening in Safari. Chrome and Firefox are both OK.

Thanks for helping in advance!


Energy Impact 1:
Energy Impact 1

Energy Impact 2:
Energy Impact 2

CPU Temperature and Fan Speed: CPU Temperature and Fan Speed

Network Activity:
Network Activity

  • 65 degrees is not really dangerous for the mac, max temp is around 100 degrees ;) It seems that your are downloading something ?
    – StrawHara
    Dec 29, 2015 at 8:04
  • The weird thing is I am not doing anything with Safari. Just randomly opened a few tabs like Google and Facebook and leave it there. Also it is not making any sense to me that an idle Safari can generate 65+ degrees.
    – siutsin
    Dec 29, 2015 at 8:08

3 Answers 3


I know this is probably a little late but I hope it helps someone else.

I found the reason Safari was using so much CPU was due to faulty permissions. It was stuck in a loop trying to access a file it couldn't.

To see if this might be an issue for you run:

sudo /usr/libexec/repair_packages --verify --standard-pkgs /

And see if there are any files wile damaged permissions. For me it was:

Permissions differ on "Library/Java", should be drwxr-xr-x , they are drwxrwxr-x .
User differs on "private/var/db/displaypolicyd", should be 0, user is 244.
Group differs on "private/var/db/displaypolicyd", should be 0, group is 244.

So it is a good chance Java permissions are the culprit. To fix run:

sudo /usr/libexec/repair_packages --repair --standard-pkgs --volume /

And then restart Safari. For me this immediately dropped CPU use from 150% to 14%.

One should note if you have 100s of faulty permissions, it could be an early sign of disk failure. As always, keep backups.

I hope this helps someone else out there.

  • 7
    Seems repair_packages is not available in macSierra. Not found here.
    – Vagner
    Oct 27, 2016 at 12:51

Did you tried to delete the caches ?

Enable 'Develop' mode in Safari (Safari -> Preferences -> Advanced -> check 'Show Develop menu in menu bar')

Under 'Develop' menu option, click on 'Empty Caches'
  • 1
    Tried, not working
    – siutsin
    Dec 29, 2015 at 8:15
  • Did you tried to disabled some safari add-ons ? Or are you using a download manager like Folx ?
    – StrawHara
    Dec 29, 2015 at 8:17
  • Also tried with removing all extensions in Safari
    – siutsin
    Dec 29, 2015 at 8:18
  • Strange... And when safari is sucking the cpu, does it take a lot of bandwidth ?
    – StrawHara
    Dec 29, 2015 at 8:22
  • Updated the question with network activity. It seems like no network activity at all.
    – siutsin
    Dec 29, 2015 at 8:27

developer mode seems to be buggy; acknowledged today by Apple with recent consumer reports with the new MacBook Pro 2016. A patch is on the way in beta testing now.

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