Previously only available as a developer edition, the new 64-bit Firefox 43 is available for those with 64-bit devices running Windows 7 and above. MAC OS X and Linux users have enjoyed a 64-bit version for quite a while, and now Windows users can take full advantage of their 64-bit environments. Microsoft Edge, Internet Explorer, and Google Chrome already offer 64-bit versions of their browsers, and it appears Mozilla is looking to keep their browser relevant and up-to-date.
Another reason Mozilla is likely providing a 64-bit Firefox version is due to online gaming. For the best experience, online gaming demands browsers that have stability and performance–something 32-bit browsers often can’t provide. Moreover, 64-bit browsers can handle more open tabs and provide better overall security than 32-bit browsers.
It’s important to note that if you have Firefox 42 and upgrade to Firefox 43, you’ll remain on the 32-bit version. In order to install Firefox 43 64-bit version, you will have to do so separately and choose the 64-bit option on the Firefox downloads page below.