It seems that I have to build my own 64-bit Firefox for Linux, as Mozilla won't support it until Firefox 4.

Why is this? It looks to me as though it works fine, although without some of the speed improvements to the Javascript engine which the 32-bit version gets.

(Edit: Yes I could run the 32-bit version but I'm trying to keep my system clear of 32-bit cruft and libraries etc, and all the plug-ins worked fine in 3.0.11 64-bit unofficial builds.)

Update : No longer relevant as Mozilla provide 64-bit builds, but they don't show them on the download pages of mozilla.org, just on the ftp site as mentioned in one of the answers below.

  • 1
    And sometimes you do need a 64 bit browser. E.g. to open very large HTML files. With a 32 bit browser on Windows the limit is about 130 MB for the file size (takes up 10 times as much in memory) - I don't know about Linux, but we sometimes get HTML files from one of our server applications of 700 - 900 MB in size. – Peter Mortensen Jul 15 '09 at 13:05
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    Use pagination... – Robert Munteanu Jul 15 '09 at 13:33

It's just the choice of your upstream packager - the linux distro. OpenSUSE provides 64-bit builds for Mozilla Firefox.


Builds of Firefox straight from Mozilla really only matter for Windows, and such, with no centralized repository of software. For us Linux folks, most of the work is done by our trust package managers, as is the case for Firefox as well. Arch Linux provides a 64-bit build, Ubuntu does, et cetera.

Just check your repo!


I assumed the browser on my laptop (running 64-bit install of Ubuntu 9.04) was a 64-bit version, is that not the case?

From the 'About Firefox' pop-up:

Mozilla/5.0 (X11; U; Linux x86_64; en-GB; rv: Gecko/2009060309 Ubuntu/9.04 (jaunty) Firefox/3.0.11

  • Yes, that is the case. I run 64bit 9.04 at home and it ships with 64bit FF. – Colin Pickard Jul 27 '09 at 14:20

While many Linux Distro provides 64 bit Firefox, you can obtain them from Mozilla's official download site, for example this one.

  • Please expand this answer. Link only answers may be removed. – soandos Jul 12 '12 at 20:12

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