Mozilla does not release a 64-bit version of Firefox except for testing. The "Nightly" release is intended only for testers and is not recommended for day-to-day use. I guess not enough advantage has been demonstrated to support a 64-bit release for regular use.

Mozilla doesn't have a release version of Firefox 64-bit for Windows operating systems. Mozilla does have Nightly alpha-level 64-bit versions for Windows, but currently they are generated to only verify that Nightly channel changes aren't being broken on 64-bit versions of Windows.

There are a few 3rd party 64-builds available, like Waterfox, but those aren't official Mozilla releases.

Advantage?

• I can tell you that the W3C HTML5 single-page spec will not load under a 32-bit browser, or barely will, it's a 14MiB HTML file. I like to be able to do ctrl-f on a document to find things I need. the multipage doesn't allow for that.

that's enough reason for us web designers.

• plus, 32-bit programs are not as secure as 64-bit from what I read.
• some of my HTML5 documents may become very similarly large.

http://www.whatwg.org/specs/web-apps/current-work/

you cannot let simple, stupid browsers like IE beat you to the punch. even chrome has a 64 bit browser (not very good, but still better than IE).

I am also busy upgrading my company's web page to HTML5 and need a reliable browser to test these changes on.

Hi Arturius, IE10 and IE11 actually are very sophisticated browsers. But I digress... Personally I do not think a browser needs a 64-bit architecture unless the goal is to enable it to use even more memory than 32-bit architectures allow, and most users who visit here seem to feel that Firefox already uses quite enough memory as it is.

Mozilla has has 64-bit Firefox for Linux and combined 32/64 for Mac OSX ever since Firefox 4.0 released March 22nd, 2011. The Win64 builds however still has some hurdles to overcome for Release.

If I install the64 bit version can I update it each day with the latest Firefox nightly build or will this be an issue seeing as it is a 3rd party version or just a testing version for Mozilla?

Hi maxmaggot, the Nightly release is maintained by Mozilla. Since it contains the latest changes with very little pre-testing, you can expect more problems with stability (more crashes) than the released version.

Thanks for this. I'll stick with the 32 bit nightlies.

Again Thanks Max

C++: in windows 64-bit, and depending on your compiler, _WIN64 is defined for 64-bit compiles, and not if it's 32-bit. mingw-w64 can be detected by looking to see if __MINGW32__ is defined. it also #defines the __MINGW64_VERSION_MAJOR and __MINGW64_VERSION_MINOR if you need a compiler version (not sure if this corresponds to gcc version). also, with mingw and mingw-w64, __GNUC__ is defined as with any gcc compiler. hope this helps. I put some of this kind of stuff down here: common c++ #defines