High CPU usage in Safari with no plugins, emptied cache, cleared history, and sometimes even no pages open

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High CPU usage in Safari with no plugins, emptied cache, cleared history, and sometimes even no pages open

I have a 16" MacBook Pro with maxed out graphics and system RAM. Very regularly, it overheats and the fans loudly spin up to max speed.

There are many causes, and I'm convinced that there is an underlying hardware issue, but one annoying thing I see often is that Safari is at 100-200% CPU usage for no obvious reason - even without any windows open, and even after having history and cache cleared, and absent any plugins.

I don't accept that 1-2 cores at 100% on an 8 core machine should cause such overheating (which is why I believe my MacBook Pro is defective), but independent of that, there is no reason that such a mature and essential program should be wasting so many resources.

MacBook Pro with Touch Bar

Posted on May 27, 2020 7:38 AM

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Answer 1

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Scott Menor Author

Level 1

24 points

May 28, 2020 11:43 AM in response to chris_g1

I booted to safe mode but to be clear - there is no way in **** that I'm going to nuke my installation and re-install macOS.

That you would even suggest that when this problem has been present literally from day one with my factory installed macOS is just staggering to me.

You're talking about taking my primary work computer and in addition to spending many hours re-installing and starting over, only to prove to you that the problem is still there as it was originally.

Does that honestly seem like a reasonable course of action to you ‽

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Answer 2

chuck_3rd

Community Specialist

May 27, 2020 7:57 PM in response to Scott Menor

Hey there Scott Menor,

Thanks for reaching out to Apple Support Communities. I understand your Mac is getting hotter than expected and Safari could be contributing to this. I’ll be happy to help.

If you haven’t already, go through the following article for some steps that could resolve this. This includes updating your Mac, resetting the SMC, and more:

Keep your Mac notebook within acceptable operating temperatures

After that, open Safari and click on Safari > Preferences from the Mac menu bar. Click on Extensions and disable those. See if this has any impact on how much CPU it’s using. If it does, enable the extensions one at a time and see if any start causing the issue.

If this doesn’t work, boot your Mac into safe mode and see if the issue continues there. Depending on the results, you’ll want to follow the steps under ‘If the issue continues in safe mode’ or ‘If the issue doesn't continue in safe mode’ from the this article:

How to use safe mode on your Mac

Take care.

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Answer 3

chris_g1

Community Specialist

May 28, 2020 11:27 AM in response to Scott Menor

Hey Scott Menor,

Thanks for going through those steps. To verify, did you reinstall macOS as stated in the safe mode article? If not, follow those steps and see if this has any impact on the issue. The following link can guide you on how to do this as well. While this should retain your user settings and files, it’s always a good idea to make a backup before doing this:

How to back up your Mac

Reinstall macOS

Also, you may want to look at Activity Monitor and see if there is any process running in the background that could be contributing to this. Take a look at this link for more detail:

How to use Activity Monitor on your Mac

Regards.

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Answer 4

chuck_3rd

Community Specialist

May 31, 2020 3:22 PM in response to Scott Menor

Hey Scott Menor,

I understand your concerns but its important to note that when reinstalling macOS, your user settings and data should be retained. Also, this helps further isolate the issue to help determine if this is something related to your Mac hardware.

Before doing the reinstall though, you can run First Aid on Macintosh HD with the steps here:

Repair a storage device in Disk Utility on Mac

You may want to check for any hardware issues using Apple Diagnostics as well:

How to use Apple Diagnostics on your Mac

Take care.

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Answer 5

Scott Menor Author

Level 1

24 points

May 27, 2020 8:01 PM in response to chuck_3rd

Thank you, Alex.

I've done all of these things multiple times and the issue persists.

I've reset SMC and PRAM, I have no extensions, I've tried clearing history and cache, it is intermittent but persists in Safe mode, The ambient temperature is 26ºC (~78ºF) with <10% humidity.

Any other suggestions ?

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Answer 6

Scott Menor Author

Level 1

24 points

May 28, 2020 9:25 AM in response to Allan Jones

Nope (also do note that the high CPU on Safari is unrelated to this and while it’s a bug that needs to be addressed, pegging 1-2 cores of an 8 core machine shouldn’t be enough to make both fans come on at full speed in a reasonable ambient temperature; that seems like a hardware problem to me)

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Answer 7

Scott Menor Author

Level 1

24 points

May 28, 2020 11:53 AM in response to chris_g1

Also if you looked at my screenshot, you can see I used top and / of course I've looked in Activity Monitor.

Even when there is nothing using a significant amount of CPU or GPU, my fans are loudly running at 50%, and my MacBook Pro is warm to the touch.

Something is wrong, and if you think running hot even while idling is operating within reasonable parameters for a $5k computer, something is wrong with you.

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