We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Mac high cpu usage

  • 2 replies
  • 8 have this problem
  • 31 views
  • Last reply by ae6dx

ae6dx
ae6dx
more options

I'm noticing very high CPU usage from Firefox as reported by OS X Activity Monitor. I have tried what is said here https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix?esab=a&as=aaq with no luck.

Is there some log file or something I can provide that will help figure out the high CPU?

I'm noticing very high CPU usage from Firefox as reported by OS X Activity Monitor. I have tried what is said here https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix?esab=a&as=aaq with no luck. Is there some log file or something I can provide that will help figure out the high CPU?

All Replies (2)

cor-el
cor-el
  • Moderator
  • Top 10 Contributor
more options

Such issues can be caused by one or more of the installed extensions.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

  • Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
  • Do NOT click the Reset button on the Safe Mode start window

See also the about:memory page. you can open about: pages via the location/address bar like you open web pages.

ae6dx
ae6dx Question owner
more options

I have already checked extensions. What exactly do you need from the about:memory page?