Mozilla on Monday announced its first developer preview of a 64-bit Windows version of Firefox.

The launch put the 64-bit edition on track to appear as a polished, ready-for-all browser by mid-May.

"Today we're happy to announce ... 64-bit builds for Firefox Developer Edition are now available on Windows, adding to the already supported platforms of OS X and Linux," wrote Dave Camp, director of developer tools, and Jason Weathersby, a technical evangelist, in a post to a company blog yesterday.

Firefox 38's Developer Edition, formerly called "Aurora," now comes in both 32- and 64-bit version for Windows. Currently, Mozilla's schedule, which launches a newly-numbered edition every six weeks, has Firefox 38 progressing through "Beta" and "Central" builds, with the latter -- the most polished edition -- releasing May 12.

Cook and Weathersby touted the 64-bit Firefox as faster and more secure, the latter due to efficiency improvements in Windows' anti-exploit ASLR (address space layout randomization) technology in 64-bit.

The biggest advantage of a 64-bit browser on a 64-bit operating system is that it can address more than the 4GB of memory available to a 32-bit application, letting users keep open hundreds of tabs without crashing the browser, or as Cook and Weathersby pointed out, run larger, more sophisticated Web apps, notably games.

Mozilla is the last 32-bit holdout among the top five providers of browsers.

Google shipped a Windows 64-bit Chrome in August 2014 and one for OS X in November, while Apple's Safari and Microsoft's Internet Explorer (IE) have had 64-bit editions on OS X and Windows since 2009 and 2006, respectively. Opera Software, the Norwegian browser maker known for its same-named desktop flagship, also offers a 64-bit edition on Windows.

The path to a 64-bit Firefox on Windows has been tortured. Although the open-source developer has long had 64-bit versions for OS X and Linux, Mozilla suspended work on one for Windows in November 2012 only to recant and restart the project a month later.

A 64-bit version of Firefox on Windows has been available on Mozilla's "Nightly" build channel, a very unpolished edition, for years.

Mozilla has another sidelined browser that it could restart: Firefox for a Windows-based touch environment.

Officially labeled as "Firefox for Windows 8 Touch," the browser was shelved almost a year ago, just days before its scheduled debut, when Mozilla cited poor adoption of Windows 8's (and Windows 8.1's) "Modern," née "Metro," touch-first mode for the decision.

But with Microsoft planning to release Windows 10 later this year -- most likely in September or October -- and aggressively push uptake by giving free upgrades to consumers running Windows 7 or Windows 8.1, Mozilla may rethink the shuttering of Firefox on touch.

At the time, Mozilla said that the code would be mothballed, available at some later date if Metro suddenly got a growth spurt.

Mozilla has not replied to questions about whether it has plans to restart Firefox on touch for Windows 10.

Meanwhile, Microsoft has announced a new browser for Windows 10. Code named "Spartan," the browser will be a fresh start for Microsoft, which will leave legacy support behind, and to the still-available IE11 or its successor. Spartan, which has yet to appear in the Windows 10 preview for the desktop and larger tablets, will be what Microsoft pushes as customers' go-to browser; it will be improved and enhanced on a much faster pace than Internet Explorer.

Firefox 38's 64-bit Developer Edition for Windows can be downloaded from Mozilla's website.