Good news: Mozilla fixed their damn browser

Firefox is fastSince the official release of Firefox 9 is today, it seems like an appropriate time to revisit my post from a few weeks ago complaining about Firefox’s poor performance on Linux to see if anything’s changed.

Good news. It has!

After my post hit Hacker News, a couple of people at Mozilla reached out to me to see if they could help run down the problem. They said they knew about the problem (which appears to center around low-level weirdness in some popular Linux filesystems), they had been working on it, and I could test out their work by switching from using the then-current release version of Firefox to using Firefox Aurora.

“Aurora” is a new stage in the Firefox release process that was introduced earlier this year. It provides an update channel that streams in new features periodically as they come in, rather than having to wait for the next full version of Firefox to get them. It’s distinct from the nightly builds that Mozilla has always made available for Firefox in that rather than just being a snapshot of the browser code as it stands at the end of each day’s work, it doesn’t include features until they’re at least somewhat fully baked, so while it’s more bleeding-edge (and therefore potentially unstable) than official Firefox betas, it’s less so (and therefore more potentially stable) than nightlies.

Anyway, I’ll try anything once, so I made the switch to Aurora (an easy thing to do, thanks to the PPAs that Mozilla kindly provides for Ubuntu users) and started using it as my everyday browser. And I was pleased to note that the slowdowns and lack of responsiveness that had been so frustrating in mainline Firefox were entirely gone. They went from “happens all the time” to “never happens, ever.” Which was awesome. Firefox felt like… well, like Firefox again.

I didn’t want to declare victory too quickly — the old problems hadn’t cropped up immediately either, they had started off slowly and gotten worse over time, so I figured I should keep using Aurora and see if they ever came back. Well, I’ve been using Aurora as my primary browser every day for a couple of months now, and they haven’t; the browser is just as fast and responsive as it was the day I switched over. So it seems safe to say at this point that Mozilla has slain this particular dragon.

Does this mean that you should switch to Aurora? No, probably not. Aurora is just a place for Mozilla to test out new ideas; things in Aurora that work well will eventually find their way into official Firefox releases, and Mozilla’s new rapid release schedule for Firefox means that you don’t have to wait six months or a year for each new version, so you should be seeing these improvements in your copy of Firefox soon. (They may even be in Firefox 9, though I can’t say for certain because I haven’t had a chance to review the complete list of fixes in that release yet.)

While it’s good to see issues like this getting fixed, I would still say that there are places where Mozilla needs to improve its process. The biggest one is how they communicate with users. Even after multiple searches through Bugzilla and various Mozilla-oriented forums, the only reason I found out that my problem was actually being worked on was because my post hit Hacker News and went viral from there. It was great that I did eventually find out, but it would have been better for Mozilla if I had been able to learn they were aware of the problem and were working on it on my own. Then I would probably never have written the post to begin with, and Mozilla wouldn’t have suffered the PR hit of having a user’s complaints about Firefox performance leading the tech news for a day. And it should be easier for me to report back to you whether or not these fixes are included in Firefox 9 than it currently is.

Even with that being said, though, I want to give credit where it’s due: Mozilla is working hard to make Firefox not just a faster browser, but the fastest browser. And from where I sit, anyway, the work is definitely paying off.



December 20, 2011
2:00 pm

firefox nightly have a really nice memory usage too, and a regular user-visible garbage collection. 150M-180M for 10 tabs (html5, css3, flash content), quite nice.


December 20, 2011
2:14 pm

Just question on the picture. Isn’t that a picture of a fox; which is a different animal than that of the fire fox? I thought Mozilla FireFox was named after the Red Panda aka Fire Fox.


December 20, 2011
2:47 pm

Never again. After how many years of a garbage browser that kept leaking memory and growing everytime to be unusable and mind-boggling memory hog and poor performance….

Never again will I give them a try when they went how many years without fixing the simplest issues of making a usuable browser.


December 20, 2011
3:10 pm

poch: Maybe, but the icon/logo for FF itself isn’t a panda

Daniel Larsson

December 20, 2011
3:51 pm

I have no idea what versions or black magic some of you must be applying, but while i do like and use FF memory usage has ALWAYS been a huge issue with the reader and it’s ‘plugin container’ easily eating 2GB of ram and randomly crashing for me.

Peter Bengtsson

December 20, 2011
3:58 pm

That’s excellent! Great! I’m not a Firefox engineer but a Mozilla web developer.

I should just add, for the sake of completeness, that if you don’t dare to play with the latest (i.e. Aurora) alternative is to run Firefox Beta which is one release cycle *between* Firefox and Aurora.

December 20, 2011
5:27 pm

Does it still balloon up to 800MB of RAM for 4 tabs?


December 20, 2011
5:43 pm

@nope: I should expect you have already submitted a bug report and associated patch to fix the simple issue then?


December 20, 2011
7:19 pm

@Daniel Larsson: Notice that the “plugin container” uses the RAM, not the browser. In other words: Flash sucks, news at 11. Flash keeps piles of memory around, and doesn’t free it. Mozilla tries to work around this problem by unloading the plugin when not in use and reloading it (without all its wasted memory) when needed again. However, depending on what tabs you keep around, the plugin may never become unused. For instance, gmail uses the Flash plugin, as does Github, as do many sites behind the scenes, in addition to the obvious candidates like YouTube. If you never close those sites, Mozilla can’t unload the Flash plugin, and it will keep using more and more memory.

Flash represents the single worst offender when it comes to browser performance and memory usage, and it doesn’t help that people often blame the browser instead of the plugin.


December 20, 2011
9:28 pm

Did they put back Browse-by-name by default?


Then they did NOT fix it. Just made it speedier.


December 20, 2011
10:43 pm

@Daniel Larsson
I will admit to flash being horrible, chromium’s solution is to implement their own flashplayer, which seems to have paid off in this regard.


December 21, 2011
1:11 am

I have to admit that Mozilla really has been listening. I noticed a lot of improvements in Firefox. Normally, my browser crashed within 2-3 hours of usage due to accumulating memory usage. Recently I managed to run 2-3 windows with around 50 tabs in over 24 hours of usage! However, the Flash plugin frequently crashes, though.


December 21, 2011
4:03 am

I’m using firefox in windows.Compared with the old versions, this version is faster, but still cannot catch up chrome.
I don’t use the firefox browser but use firefox 9 engine in Avant browser, also the webkit 17 engine in it. If you open a same page in both firefox engine and chrome engine, you will find the difference.

Satvik Jagannath

December 21, 2011
8:35 am

I’m using Firefox from almost 7 years. I am a Firefox fan!
I can assure you one thing, Firefox is the fastest and the most stable browser with less memory usage! This is unbeatable!

Chrome spoils your memory usage. Its horrible.

And IE, no words. Worst ever. Though IE 9 is better than what people had expected.


December 21, 2011
9:04 am

I’m happy to be part of this in your previous post. Nice to see Mozilla developers listening to their passionate users. I really hope the best for Firefox!

Forensic Penguin2

December 21, 2011
9:32 am

I loaded the Aurora channel and am using FF in Linux. Seems a lot more responsive. It carried all of my plug-ins over, and settings were there, too. I prefer FF to Chromium, both have uses for both depending on the situation.

Asa Dotzler

December 21, 2011
2:21 pm

Jason, it’s great to hear that you’re having a better experience with the Aurora build.

There are several ways that you and others can report issues to Mozilla. From most difficult to least:

File a bug report at This requires setting up a bugzilla account but after that hurdle we do hold your hand through the process pretty well. (tip: if it’s a bug in the Firefox user interface, pick “Firefox”. if it’s a bug in a web page or Firefox’s “back end” then pick “Core”.

Join us on IRC and tell me about the problem. The server is and I’m “Asa” or “asadotzler”.

Submit feedback from Firefox’s help menu.

Tweet me or other famous mozillians about it. I’m asadotzler on twitter or just tweet with “firefox” in your comment and our “Army of Awesome” will hopefully catch it and offer to help.

Forensic Penguin2

December 21, 2011
6:13 pm

Just a visit back to tell you that I changed to Aurora on my netbook, as well as my laptop. Memory usage is way down, even with five tabs loaded, and seems faster than Chromium. The version reports Aurora 10.0a2
Waiting to see what happens before I change my desktop, though. Really only use if for forensic stuff.


December 29, 2011
10:46 pm

I won’t trust aurora again. I stuffed up all my saved bookmarks by deleting it. I have a business and relied on these bookmarks. The warning that all personal stuff will be deleted was not clear enough instating Firefox bookmarks go as well. People i notice now have been complaing about this for years. Why is the problem not fixed? My bookmarks were years of accumulated work.

Selji Okita

May 27, 2012
12:46 pm

I’m using Firefox from almost 5 years. I am a Firefox fan too!
But I think Firefox go bad with video on web :(

Mozilla Firefox’s mascot the RED FOX

August 21, 2013
5:12 am

Mozilla Firefox’s mascot is a red fox on fire, not a red panda. “Firefox” is just the Chinese name for the red panda, has nothing to do with Mozilla’s browser.

I’m sorry, but I’m a fox lover and I hate it when they say that Mozilla’s mascot is a red panda. Every time someone says that as a fact, I get angry.

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