This website provides Experimental Mozilla Firefox and Thunderbird Community Edition builds, sometimes known as Unofficial Builds, that are compiler and code optimized to provide better performance though equivalent behaviour to Official Mozilla builds.

We host Version 1.5 Release Candidate builds for Firefox and Thunderbird for the Windows XP x64 edition platform and also some Windows 32-bit builds for SSE and SSE2 platforms. SSE broadly refers to the Intel Pentium 3 and some AMD processors and SSE2 broadly refers to Intel Pentium 4, Pentium M and Xeon processors along with AMD Athlon and Opteron processors that support the SSE2 instruction set running. After progress in these areas, we'll look at builds for Mac OSX on G4 and G5 processors and then 32-bit Linux.

Most of the builds here will be builds of pre-release software and are therefore experimental so we discourage their use for production purposes.

Official Mozilla builds are available at

We will be adding pages on a few other topics as we have time.


We attempt to ensure the accuracy of the information, links available on this site and on other sites but we assume no legal liability or responsibility for the completeness, accuracy or usefulness of any of the information here. The information provided here is provided for the end-user's information and is provided strictly "as is." We make no representation or warranty, express or implied, with-regard-to the information at this site or at other sites linked to by this site.

Software downloaded from the Vector64 web site or is provided "as is" without warranty of any kind, either express or implied, including, but not limited to, the implied warranties of fitness for a purpose, or the warranty of non-infringement. We also do not guarantee to provide support for any problems resulting from the use of software available at this site.

We specifically do not warranty that the software will meet your requirements, that it will be secure, that it will be without errors, that it will be provided in a timely manner, that the results from the software will be accurate or reliable, that software quality will meet your expectations, that bugs in the software at this site will be corrected. We also assume no responsibility for errors or ommissions in the software at this website.

Vector64 will  not be liable to you or any third parties for damages of any kind or damages resulting from the loss of data, profits, hardware or software in connection with the use of the software at this site. Software downloaded from this site is done at your own risk and with the agreement that you will be solely responsible for any damage to your computer hardware, operating system, network and software or any loss of data that results from using software from this website.


Making Your Own Builds

If you'd like to do your own builds just for the satisfaction of being able to do so or to share them with others or to put in some of your own personal customizations, you can start by reading the directions in the Build Documentation document at the mozilla developer center.

Building Firefox or Thunderbird usually requires a certain level of hardware and development software and assembling the pieces can take quite a bit of effort. It can take quite some time to build on older and slower machines or those that don't have a lot of memory. And it can be a frustrating process on some platforms as the build configuration can be very picky and fail for non-obvious reasons for the smallest problem.

The mozillaZine Third Party/Unofficial Builds forum is a good place to ask questions about building or to get help if you find that you have a problem building Firefox or Thunderbird. It's always helpful if you post a screenful of lines around the error message and provide your .mozconfig file and the environment setup script that you're using. In general, builders are pretty helpful if they can help but builders have busy lives too and it can sometimes take some time to get a reponse to your questions.

We have some notes for builders in my Builders Corner Page that we find useful from time to time. We plan to add to this list over time.

Other Miscellaneous Stuff

My blog
Firefox Performance Preferences
Future Performance Ideas and Open Bug List
Other Unofficial Builders
Programming Problems and Solutions
Trading Pages
Hardware Page
Software Page
Home Education Pages
News link page
MCC Classes
UML Classes
Bugzillas of interest

Updated April 12, 2009. For comments and questions, send email to Vector.x64 @ (without the spaces).