Mozilla now automatically delivers the 64-bit version of Firefox to Windows users with compatible hardware, the open-source developer said this week. (Firefox can be ">downloaded here.)
"Users on 64-bit Windows who download Firefox will now get our 64-bit version by default," Mozilla explained in a Monday post to a company blog.
The 64-bit version of Firefox 55, which Mozilla released on Aug. 8, is now installed by default on all 64-bit hardware running a 64-bit edition of Windows. The only other requirement is that the personal computer must be equipped with at least 2GB of RAM, or system memory.
A 64-bit browser on a 64-bit operating system can address more than the 4GB of memory available to a 32-bit application, letting users keep open hundreds of tabs, and run larger, more sophisticated web apps. Mozilla's rivals have offered 64-bit browsers for, in some cases, years. Google shipped a Windows 64-bit Chrome in August 2014 and one for macOS in November of that year, while Apple's Safari and Microsoft's Internet Explorer (IE) have had 64-bit editions on macOS and Windows since 2009 and 2006, respectively. Microsoft's Edge is 64-bit as well.
Mozilla's move was just the latest in a very long process to replace the older 32-bit Firefox with the more capable 64-bit version. Although Mozilla has long had 64-bit versions for macOS and Linux, it shelved work on one for Windows in November 2012, only to recant and restart the project a month later.
Mozilla previewed Firefox 64-bit on Windows in March 2015, and shipped a stable edition in December of that year.
A 64-bit Firefox has been increasingly important for Mozilla as more users switch to a 64-bit operating system, including Windows 10, which comes in both bit flavors.
Mozilla has not taken a final step to automatically migrate all eligible 32-bit Firefox users to the 64-bit browser, but plans to do just that in early October when Firefox 56 debuts. The same requirements - 2GB or more of RAM, 64-bit Windows 7 or later - will be used for the auto-migration.
Users, including those in managed environments, who do not want to be automatically upgraded to 64-bit Firefox this fall can opt out by setting a Windows registry key as outlined here.
Firefox users can still manually download a 32-bit copy of the browser from Mozilla's website (it's the link in the first column, the one marked simply "Windows").