Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

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.

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

Firefox uses large amounts of memory that bring everything to a halt

  • 9 replies
  • 0 have this problem
  • 5 views
  • Last reply by cor-el

more options

Since the last update (earlier this week) firefox uses large amounts of memory. It shows in the windows task manager 20 and more instances of firefox being open and one of them using 85%-90% of the available memory. I looked up help articles regarding this issue and one of them mentioned to "Delete content-prefs.sqlite file". When I do that it will help for a short period of time but then the issue is happening again. I'm using Windows 11 64 bit.

I'd appreciate some advice on how to deal with this.

Since the last update (earlier this week) firefox uses large amounts of memory. It shows in the windows task manager 20 and more instances of firefox being open and one of them using 85%-90% of the available memory. I looked up help articles regarding this issue and one of them mentioned to "Delete content-prefs.sqlite file". When I do that it will help for a short period of time but then the issue is happening again. I'm using Windows 11 64 bit. I'd appreciate some advice on how to deal with this.

All Replies (9)

more options

Can we get a screenshot of task manager performance tab? It will be helpful to see what your working with.

more options

Press Shift+Esc to see the Firefox task manager and identify the processes causing issues.

more options

jonzn4SUSE said

Can we get a screenshot of task manager performance tab? It will be helpful to see what your working with.
more options

That's not the performance tab. Here's a bit more info on what's going on.

Introducing Firefox’s new Site Isolation Security Architecture https://hacks.mozilla.org/2021/05/introducing-firefox-new-site-isolation-security-architecture/

Firefox's Project Fission: better security and more processes https://www.ghacks.net/2019/02/07/firefoxs-project-fission-better-security-and-more-processes/

Enable or Disable Fission in Firefox https://www.ghacks.net/2020/09/20/you-can-try-firefoxs-site-isolation-feature-fission-in-nightly-now/

Another user with the same issue. https://support.mozilla.org/en-US/questions/1401082#answer-1557050

Modified by jonzn4SUSE

more options

Sorry, I didn't know until now that the browser had a taskmanager. Here's the screenshot.

more options

Note that there have been performance issues reported with Kaspersky.

more options

You can reduce the number of non-essential processes by installing a blocker like uBlock Origin.

To investigate a high-usage process, hover over it in the Process Manager and click the speedometer icon.

more options

Sidiana said

Sorry, I didn't know until now that the browser had a taskmanager. Here's the screenshot.

Not the browser, but Windows Task manager Performance Tab.

more options

Firefox comes with a Task Manager as one of the developer tools (about:processes; Shift+Escape).