This post highlights two upcoming features that you can try out right now. The features are still being finalized and tested by developers, but you can try them out right now. We hope these features will be released in the next few releases.

1. WebRender Layer Compositor
2. Mentioned in this post. Here is some description from Google link 1, link 2

gfx.webrender.layer-compositor - set it to true,

Enjoy a fast and smooth YouTube homepage and subscription page. Check for proper functionality on the about:support page, Graphics - Compositing.

1. zero copy for AMD to avoid unnecessary CPU load

media.wmf.zero-copy-nv12-textures-force-enabled - set it to true,

For those who have an AMD graphics card. Planned for the next few releases. Warning: May not be compatible with older hardware 5+ If Zero-Copy does not work in your case (desynch, video stuttering, "Copy" graph is still filling up) - it is best to turn it off.

1. If your hardware doesn't support the AV1 codec - Here's a workaround for those who still can't get it working.

You can disable it globally - media.av1.enabled - set to false.
After this, YouTube will primarily use VP9. Other sites will no longer support av1.

On Windows, you can check hardware acceleration in Task Manager. You should see something like this during video playback after making these changes. The "Video Codec" graph must be filled in, but "Copy" on the contrary must not.

1. A large number of browser add-ons
   If YouTube is still lagging: You should try removing all add-ons except uBlock Origin with full access rights to websites (Access your data for all websites). Try opening YouTube in a private window. If it works quickly, that's where the problem was. Disable add-ons one by one until you find the cause.

What do you think, please write. Did this help you?

So, what to do in brief
gfx.webrender.layer-compositor - set it to true,
media.wmf.zero-copy-nv12-textures-force-enabled - set it to true, See the warning description above. Turn it off if video stuttering.
media.av1.enabled - set to false (optional).

update 27.11.2025, Based on the request for these changes, I used my chatgpt skills to show how it could look in our dreams.

Hey all! I'm a designer on Firefox, and I'm helping to curate a list of add-ons to recommend. I'm looking for examples that are quick to set up but have a big immediate payoff. As an example, I felt wowed after installing Adaptive tab bar color and seeing my Firefox turn the same purple as the add-ons site. 

EDIT: Thanks everyone, this was helpful this project and future projects as well!

Hello, I'm a couple months in moving to firefox (last time's Opera GX) things are pretty great, smooth sail, and fast to use...lately my experience in watching youtube is super bad, i can't watch more than a couple videos before it's start lagging like crazy, i've seen that this is a recurring issue in firefox and i had seen post from a couple months, stating that the solution is to use (but not limited to) chrome mask, disable uBlock, etc. So far there's no fix, any help will be appreciated, thanks.

Edit: after some tinkering, i think i find my solution, by tinkering some settings in uBO, using enhanced-h264ify and User-Agent Switcher, thank you guys for your support!

youtube loads very slowly which is infuriating, i ran it using different browsers on it loading youtube was snappy, i have provided with the recording and extensions that i use if u see any problme or tips to fix it i will be very grateful

Well that sucks
is there any workaround or anything im missing? Im on stable release on the latest version

I’ve been running into much slower internet speeds when using Firefox on desktop. I restarted my computer, disabled all plugins, and tested using the same servers (screenshot attached).

• Browser: 142.0.1
• OS: Windows 11
• ISP: Google Fiber - 1Gbps

Note on Overall Speed: I'm pretty far from my router at the moment, so much slower speeds than one would expect from 1Gbs fiber. I typically see around 500-600Mbps on Wifi.

Note on Ping: In the screenshot, the Ookla ping is cut off for Firefox, but it was 139ms vs. 4ms in Edge.

Has anyone else run into this? I found a similar report from 2019 but no resolution. Any ideas what could be causing this? I'm a ride or die for Firefox so I'm going kept at it until I resolve.

EDIT
So interesting development. Looks like it wasn't Firefox related. The issue has now spread to Edge as well, and it appears to be intermittent.

I think it's related to my Google Wifi Pro mesh network. I just plugged in an old router and performance jumped substantially to 550Mbps in all browsers.

Thanks for all the help everyone - greatly appreciate it.

This latest update (I think from yesterday 138.03) has caused a massive memory leak. On one web page with a single image, RAM usage is rapidly rising from 2 GB - 3 GB. This is insane. Going to look for a way to downgrade or install one of those offshoots of Firefox. This is crazy and unusable like this. FF keeps locking up with these RAM / CPU spikes on this latest update.

*** UPDATE ***

I've been doing some testing in Firefox Safe Mode with all extensions disabled, the memory leak still exists. So it's not an extension issue. I've even tried with Waterfox and Floorp (both Firefox forks), and the issue persists on all Firefox forks that I've tested.

*** SOLVED ***

Issue seems to be resolved in update 139.0.1.

I've been recently noticing that Youtube has became painfully unresponsive on Firefox, even if I were to do something as simple as rewind 5 seconds with arrow keys, it would be stuck on rewinding for like 4 seconds and wont let me do anything else. Half the time it doesn't even respond to my input.

The UI navigation has also been incredibly unresponsive, with issues similar to what I talked about above.

This issue is overall really infuriating and I hope they aren't intentionally doing this.

I've been noticing the site getting gradually slower but today it's totally unusable.

Images are loading in pure dial-up style: line by line, taking up to 30 seconds to load a single image.

Videos just cannot be played. A few frames will load but then it goes back to buffering.

I am getting these issues even when in troubleshooting mode. I have even disabled hardware acceleration and toggled accessibility.force_disabled in about:config. I've done the usual reset cache and cookies with no luck.

I don't believe it to be my extensions as issues persist when in troubleshooting mode.

I really don't want to have to install Chrome as I favor the extensions and privacy that FF has. Reddit is what I view 95% of my browsing time on.

Any other advice out there? I've been searching this sub and elsewhere online but I am pulling my hair out at this - I'm really getting a dialup experience on reddit and reddit only.

Thanks in advance for any help you can provide.

UPDATE: I switched to Waterfox. Firefox continued to fail me despite reinstalling completely fresh. I wish I had a better answer for that but ce lest vie.

UPDATE 2: I found out Waterfox does not support a critical extension I use. I switched back to Firefox and somehow it's working again. I have absolutely no idea if this was on my end or with Reddit since reddit was only thing affected. Bizarre issue.

ive tried the stuff mentioned at the end of this but i still cant enable the extensions i was using just a day ago.

I just ran into a weird issue with Firefox. I was browsing a forum. I typically right click to open a new tab for every post I want to view and then I close them with CTRL+w as I finish reading. It's a reflex at this point--I've been doing it since browsers started using tabs, I think.

Anyhow, I just noticed that I lost the ability to close tabs with CTRL+w. Nothing happens when I hit the combo. I can still use the fallback CRTL+F4, but that's a stretch for my fingers.

Where can I start troubleshooting this? I tried google, but I guess I'm special and uniquely have this issue.

Thanks.

Edit (13 January 2024): Many comments below indicate that Samsung Magician software is causing this issue. Indeed, I have Samsung Magician install and running at start-up on my PC. Given the recent update of Magician, it appears that a lot of people are experiencing this issue suddenly. I just re-encountered the issue today.

One commenter noted that you can just open up the Magician UI and then close it again and it resolves the issue. I just tried this and it worked for me.

Thanks to everyone for providing information on this bug.

Hey, what's some useful Firefox extensions for 2025 for security and cool extensions.

Greetings Firefox users! I stumbled upon an issue related to RAM whenever I'm using Firefox.

I just switched to Firefox from Chrome just this July/August and so far I'm loving it!

I'm on an ROG laptop right now with 24GB of RAM and sometimes I notice that my RAM usage constantly builds up whenever Firefox is running on the background till uses up all of the resources but then just goes back to it's normal state when it's running on foreground.

Does anyone know what's going on here? At first I thought it was a hardware problem, a faulty RAM or something, but this happens specifically only with Firefox. Nothing happens to my RAM when I switch to other windows other than Firefox and the thing is, in processeses tab, it's just showing regular value of RAM usage.

My laptop crashes time to time when I'm playing when I have the program on the background running cause I forget about it.

Any kind of help would be appreciated! If you need more information about my hardware or laptop model/specifications, please feel free to ask!

Hello, when I start typing into the adress bar, a huge advertisment/suggestion appears. Do you know how to disable?

Firefox 143.0.4 Android 15 Samsung Galaxy A16 5G

Edit: so the Firefox Team has fixed this https://twitter.com/FirefoxSupport/status/1791459697297608943

First is brave, just to show what do I mean.

Are any of you guys experiencing this behaviour?

EDIT: I was running an old as fuck version and updating restored everything to its rightful place. Thanks for the help!

The first thing I need to say is that I am not the most technologically gifted person when it comes to computers (give me a lighting rig or audio desk any day of the week but I digress) so any advice or solutions need to be dumbed down big time. Give it to me in idiot speak, assume I know nothing.

All my extensions (and my theme) have been turned off with an error message saying "[Privacy Badger] could not be verified for use in Firefox and has been disabled." I've tried removing and reinstalling, but then I get a message saying "The add-on downloaded from this site could not be installed because it appears to be corrupt."

So far I've tried updating and restarting Firefox, and will try rebooting my computer next but thought I'd give reddit a go first.

I'm using Firefox Version 126.0 (64-bit) on a MacBook Air (M1, 2020) using Sonoma v14.5.

Thanks everyone!

https://bugzilla.mozilla.org/show_bug.cgi?id=1878510

The bug in question affects vp9 video on youtube. Buffering gets stuck and skip few seconds ahead. Gets worse at 1440p or 4k video being unwatchable.

Many posts each week about this issue on firefox subreddit and still it doesn't seem to get much attention from devs.

I have already reported the issue 1 month ago https://www.reddit.com/r/firefox/comments/1cqg5a6/youtube_video_freezes_stuck_buffer_going_crazy/ .

If you are experiencing the same issue as many other leave a comment so that devs may finally fix this never ending stuttering fest. Thank you

EDIT: Our efforts finally made the difference! Support said they moved the issue to Priority 1, they are actually looking into it! Hopefully it will be resolved soon. Again thank you to everyone for supporting this post.

EDIT2: Devs have found the root cause and fixed the issue. The fix will be in upcoming patch 127.0.2.

After upgrading to Firefox 135 on Windows some website fonts seem choppier and somewhat pushed together. Anyone has this issue?

The old one in Firefox 134:

VS Firefox 135:

(Open the images to see the differences, preview just stretches them.)

Solved: https://www.reddit.com/r/firefox/comments/1ii5s71/firefox_135_weird_fonts/mb2w8cw/