Many different Web browsers are built on Mozilla's open-source Firefox project, including Waterfox, a 64-bit version of Firefox. Waterfox takes advantage of a variety of speed-boosting technologies found in most current Intel CPUs and the latest AMD processors, too, such as SSE3, AVX, and Jemalloc. Of course, while your Internet connection's speed and reliability will have a much greater impact on your day-to-day browsing speed than your browser will, a 64-bit browser offers some advantages in 64-bit Windows, such as increased speed and improved stress handling. The 64-bit Waterfox is also available in a fully portable version for users who prefer portable programs or who want a portable 64-bit Web browser for their USB drive. We pitted it against top-ranked browsers in two separate 64-bit Windows installations, Home Premium and Ultimate. We also tried Waterfox Portable with and without standard Firefox installed.
The biggest difference most users will see between Firefox and Waterfox (installed or portable) is the deep-blue Waterfox Start button and blue logo. Waterfox automatically imported our user data from our existing Firefox installation. If you open Waterfox and then open Firefox, the pages will open in Waterfox, and vice versa: If we had Firefox open, clicking the Waterfox icon opened a new page in Firefox (which is why we tried Waterfox with and without Firefox installed). Other than that, Waterfox looks and behaves exactly like what it is, Firefox with some fancy tuning under the hood.
We ran numerous bandwidth speed tests on Waterfox Portable, the installed Waterfox, Firefox 18, Internet Explorer 9 32-bit and 64-bit, Opera, and Google Chrome. Both the installed and portable versions of Waterfox loaded quickly and were very similar to the others in performance, though none dethroned the reigning speed champ, Chrome. The installed Waterfox clearly bested the portable version, which has been our experience with portable browsers. But both Waterfox versions seemed fast and stable in actual browsing. Of course, all the major Web browsers perform quite well in most conditions; we suggest trying each of them since they're all free. But if you want an up-to-date, fully portable 64-bit browser, Waterfox Portable is the obvious choice.