Upcoming Firefox Performance Improvements

Martin Brinkmann
Feb 28, 2010
Updated • Jun 19, 2016

If you have followed the news in the last days about Firefox's new JavaScript engine and the implementation of gpu hardware acceleration, you can stop reading here.

Everyone else, especially Mozilla Firefox users among them, may find it interesting that Mozilla announced plans to improve the performance of the Firefox web browser.

Firefox is lacking behind especially when it comes to JavaScript execution as browsers such as Google Chrome or Opera are both offering better performance right now. That's a cause for concern for many Firefox users as JavaScript is probably what is impacting browser performance the most currently.

Firefox Performance Improvements

Mozilla employees made several announcements in the past two days that provide details about upcoming changes to the browser's performance.

The first big upcoming improvement will be a new JavaScript engine called JaegerMonkey which in its current stage speeds up the JavaScript performance of the web browser by 30% to 45% which lots of room for improvement.

It will take some time before the new engine will be included in an official Firefox release, but the time will come, and it will be interesting to see how that new engine improves JavaScript execution in Firefox.

With JaegerMonkey enabled, Firefox should close the gap at least to a degree to the better JavaScript performance of Google Chrome.

GPU Acceleration

The second big change is the introduction of gpu hardware acceleration in Firefox nightly builds.

Firefox nightly builds are developer builds, and it will take some time before the new feature will land in stable versions of Firefox.

The feature is currently turned off by default in nightly builds as well and the developers state that there are bugs and add-on incompatibilities that need to be resolved first.

Firefox users who want to give it a go can download the latest nightly build and enable the feature by doing the following:

1. Enter 'about:config'
2. Click through the warning, if necessary
3. Enter gfx.font in the 'Filter' box
4. Double-click on 'gfx.font_rendering.directwrite.enabled' to set it to true
5. Below this, right click and select New > Integer to add a pref setting
6. Enter 'mozilla.widget.render-mode' for the preference name, 6 for the value
7. Restart

Make sure to backup the web browser with a tool like Mozbackup before trying any of those new features as some users have already reported that it can make the browser crash.

Update: GPU Acceleration is part of Firefox now and does not need to be enabled anymore. Firefox users who want to disable it need to do the following:

  1. Load about:preferences#advanced in the browser's address bar.
  2. Under General, remove the checkmark of "Use hardware acceleration when available".
Upcoming Firefox Performance Improvements
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Upcoming Firefox Performance Improvements
Mozilla announced recently that two major performance improvements would be coming to the Firefox web browser soon.
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  1. Transcontinental said on March 6, 2010 at 4:12 pm

    By now I use “Memory Fox” (new version available) and “MinimizeToTray Plus” (which also minimizes on exit as an option) Firefox extensions, and the result is having access to Firefox (after initial cold start of course) in 0+ seconds with a RAM occupation under 30MB when Firefox “closed” or minimized.
    Works nice, with 80 extensions.

  2. Bruno said on March 2, 2010 at 4:23 pm

    I’m not to sure the fascination for this start up time. The only thing that I look for is the main performance of the browser itself. I’ve been using Firefox since it was called Phoenix (I think), and it’s never failed me. I think FF is much more smother than the other browsers, and the pages seems to render better. I’ve tried Chrome & Chromium, and they aren’t bad at all but I’ll stick with the Fox.

  3. Mike J said on March 1, 2010 at 3:41 pm

    You may find an overall speed improvement in Ff with this:

    I have used it for a bout two years, with several versions of Firefox. I have had no problems, but make no promises either.

  4. Jojo said on February 28, 2010 at 10:24 pm

    @Dan – I’ve experimented with Memory Fox. It doesn’t work well (in at least the 1.3 version and backward). One very major problem is that it completely overwrites the application event log in Windows, obliterating any messages any other app writes there.

    He is supposed to fix this problem is the 1.4 release. Is that version released yet?

    I am also not sure of what MF is really doing to release memory. Each add-on allocates it’s own memory and is supposed to manage that memory. I am not sure that another add-on would have any ability to control what another add-on is doing.

    1. Dan said on March 1, 2010 at 4:48 pm

      @Jojo — Memory Fox is still at version 1.3. I never knew that about the Application Event Log; just checked and it’s true! No idea why that should be happening. Thanks for that info.

      1. Jojo said on March 1, 2010 at 10:53 pm

        @Dan – Why should “it” (Event log overwrite) be happening?

        It is solely because the application chooses to write a new event log record. He needs to turn this off. Apparently, since he hasn’t fixed it yet, it must be more difficult than simply removing the code statement that makes the call to write the record. Or he is lazy.

  5. Dan said on February 28, 2010 at 10:00 pm

    @Jojo: check out the Memory Fox add-on. It periodically frees up most of the memory Firefox uses… works wonders here and allows me to keep Firefox running as long as I like.

  6. Jojo said on February 28, 2010 at 9:25 pm

    @libeco – Are you using FF 3.6? I find startup speed to be very quick (and I have around 60 tabs that need to be opened).

    IMO, what FF really needs to address is memory allocation and freeing. I have to shut FF down each day before I go to bed to get it to release all the memory it it has allocated.

    I just started FF about one hour ago and I am nearly up to 600k total memory usage, By the end of today, I will likely be over 1gb, maybe even 1.2GB!

    Yes, I know that my memory issues might be due to the 50 or so add-on’s that I have installed. But unless FF gives me the tools to monitor/manage individual add-on’s memory use, then there is nothing I can do but blame FF (short of uninstalling add-on’s but I don’t have any intention of doing this).

    1. libeco said on February 28, 2010 at 10:13 pm

      @Jojo: Startup on my 2,5 year old Core 2 Duo T5600 (1,83GHz) with 4 GB RAM laptop takes 10-15 seconds. Memory consumption is huge too. Maxthon is still my preferred browser (fastest I have), even though there’re quite some disadvantages nowadays. It’s faster than Chrome, IE8, and Opera (in that order).

      I do have some web development modules installed as that’s the only reason I use firefox.

  7. somenam123 said on February 28, 2010 at 8:19 pm

    you can also set html5.enable = true

  8. libeco said on February 28, 2010 at 7:50 pm

    If only they would address the main issue: startup speed!

    1. David said on March 1, 2010 at 10:16 am

      A slow start-up speed has more to do with the perception and selective loading in other browsers. I did a side by side comparison of Chrome and a clean profile of FF (no addons) a while back, both loading my homepage Google instead of Chrome with it’s cute homepage. Sure enough Chrome’s chrome came up in 1/2 a sec and FF’s about 2 sec. The actual page content happened to be slightly faster on FF though at around 3 seconds.

      1. libeco said on March 1, 2010 at 11:40 am

        In the end it’s the only thing that matters. No matter how fast other users test it, if it’s slow for me, it might be perception… but it’s slow!

    2. Bob said on February 28, 2010 at 11:55 pm

      I know i wish they would but i bet that they all have super computers and can’t tell what the problem is.Within the 2 minutes i use some other of my 9 bowsers.

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