Big Sur 11.6.3 Safari 15.3 high CPU bug

[mick2]

2020 Intel MBA 16GB i5. After update to Big Sur 11.6.3 and Safari 15.3, opening Safari causes CPU to max out on all threads, and temps to hit 100degsC.

Has anyone else got this issue? The issue *doesnt* occur on my M1 Pro under Monterey so am unclear whether this is an intel or a Big Sur thing. The issue only started after the 11.6.3 Safari 15.3 updates earlier today.

 

[MalcolmJID]

I'm not seeing this on my late-2013 rMBP which I updated to 11.6.3 and 15.3 last night.

 

[mick2]

Thanks.

I've narrowed the issue down to Safari on Amazon Prime / Netflix / regional UK catch up TV players. Going to any of these sites on Safari 15.3 results in the browser locking up & CPU hitting 100%.

As no-one else has chimed in it's looking like something specific to my machine.

 

[doweio]

Me too.

MBP 2018 15". Safari updated and now hits 100% CPU. Just looking into which of my open tabs might be causing this...

 

[mick2]

I deleted all my open tabs, made sure no extensions were running, but the problem remained. I've just updated the MBA to Big Sur Monterey and this seems to have fixed things.

 

[MalcolmJID]

I deleted all my open tabs, made sure no extensions were running, but the problem remained. I've just updated the MBA to Big Sur and this seems to have fixed things.

Do you mean updated to Monterey?

I just tried Netflix and Prime on my end and I'm not seeing 100% CPU. That includes other tabs being open and extensions still running, including an ad-blocker.

 

[mick2]

Do you mean updated to Monterey?

I just tried Netflix and Prime on my end and I'm not seeing 100% CPU. That includes other tabs being open and extensions still running, including an ad-blocker.

Sorry, yes Monterey. When I went to Netflix / Prime, the landing pages loaded (slowly) but links etc on them were largely 'unclickable', ie the pages felt frozen; likely because of the CPU maxing out.

All still seems back to normal so far after moving to 12.2...

 

[doweio]

FWIW, I closed all tabs one by one and saw no difference. One tab or many, the problem remained when testing.

I won't be upgrading to Monterey yet, but since rebooting and in general usage, the problem seems to have also "gone away".... at least, for now.

 

[Alx56]

Hi I have been experiencing this exact same issue on my mac air m1 2020 for the last 5 months or so. I'm running the most recent version of safari as of March 2022. Every now and then I search for something on google and the page doesn't fully load and I am unable to click anything unless it is in the right spatial position as if it was normal. Also, if I click the search bar on the top it reloads the page and progresses whatever I just clicked. I noticed it occurs randomly but especially when many tabs are open. It could be fixed if it command +q quit safari and reopen it. I tried to disable extensions, remove all cookies, reboot into safe mode but nothing helps.

Did anyone figure their issues out yet? Mine might be the same or connected. Google Chrome does not have this issue as far as I know.