Firefox Community Forum

Hi everyone,

I’ve noticed that Firefox tends to use a lot of memory when I run several browser-based tools at once — especially web calculators or dashboards that update data dynamically.

For example, when I’m testing a lightweight web calculation app (something similar to a gratuity calculator that updates values in real time), Firefox memory usage slowly increases, and sometimes the browser even freezes if multiple tabs are open.

I’ve already tried:

Clearing cache and disabling extensions

Running in Safe Mode

Using hardware acceleration on/off

Still, the problem persists.

So I’d like to ask:

1. Are there any specific settings or flags that can help manage memory usage better for interactive web tools?

2. Does Firefox handle JavaScript-heavy calculations differently compared to Chromium-based browsers?

3. Any recommended performance tweaks for developers testing such tools locally?

Would really appreciate advice from anyone who’s optimized Firefox for this kind of lightweight, web-app testing.

Thanks in advance! 🙏 bold text

Your browser dead ass just doesn't respond when I click on it. I have a new mac mini 4 and have the latest update for firefox. it's absolute dogshit to be honest. I'm lucky if the browser lets me click on anything, eg., bookmarks, add-ons, history are nonfunctional. Also my tabs on the browser get squished together and superimposed such that 2-3 separate tabs appear as though they are one tab. I have never had an issue like this before when using firefox. I don't encounter the issue with safari or chrome, but I don't like those browsers. Do you have insight as to why firefox mozilla is suddently ass?

Firefox not responding on macbook M4 Macos Tahoe 26.0 I tried restarting Firefox I tried restarting my macbook But everything repeats. Use Firefox for a while and it freezes again. Tôi sử dụng Firefox mới nhất: 143.0.1

I've uninstalled every profile and installation of firefox. All addons are gone.

Upon reinstalling regular firefox, doing refresh, and syncing my account, the browser immediately freezes.

This issue has started within the past week. I've not done any major changes to my computer or firefox in general. Edge browser does not have this issue.

about:processes also freezes, making troubleshooting difficult.

I'm currently running firefox without syncing at the moment, but this isn't an ideal long term solution.

Hi, I’ve noticed that Firefox often uses a lot of memory when I have multiple tabs open, even more than Chrome or Edge on the same number of tabs. Sometimes it slows down my system or makes switching between tabs laggy.

Is this normal behavior, or is there a way to reduce Firefox’s RAM usage without losing performance? Are there specific settings, add-ons, or troubleshooting steps I should try?

Thanks in advance!

I know this probably sounds odd but I'm not imagining it. I like many people I live with many tabs open at once. Since the 143 update I come back to my computer the next morning and many of my tabs, specifically my gmail tab and many others will not work. (Oddly I've noticed some random tabs will still work, I have no idea why) I can close the tab and try to reopen gmail in a new tab and it just sits there trying to open but it will not. I've waited 20 minutes. Not until I close firefox and restore my last session will it again work properly. Is there a bug/glitch or is there some setting I need to adjust. I don't want to have to close my firefox everyday. Edge is not having this same issue, so I'm pretty sure it's not a problem with my specific machine. It's like Firefox just decides to quit when I go to bed. I know it sounds crazy.

https://www.mlb.com/gameday/braves-vs-nationals/2025/09/17/776286/live

this site at mlb.com or any site showing a live game eventually freezes up and cannot be closed normally. task manager or re-boot is only way out, starting over with a new instance of firefox after ending all firefoxes.

this has been happening just this past few days, after firefox updated to 143.0 on windows 11 using defender, no other screwed up security software.

firefox needs to fix this, it is not likely anything with the site but rather with firefox latest update, as this has always worked before on this same computer.

Dennis Coleman

whenever i scroll trough a website in firefox, the ewperience is very laggy, feels like its 15fps. i have done basic things like disabling hardware acceleration, smooth smooth scrolling.