Waterfox - 64 bit version of Firefox
Firefox Nightly builds are also 64 bit, but Waterfox is generally more stable. Waterfox is a high performance browser based on the Mozilla platform. Made specifically for 64-Bit systems. It is compiled in Intel's C++ Compiler. ICC is known to generally produce faster code than other compilers, at least on Intel's own CPUs. It makes use of newer CPU features that allow fewer instructions to manipulate more data at once. It uses Jemalloc - a more scalable memory allocation library than most. The compiler uses profile-guided optimizations, which means that it generates an instrumented build that measures where CPU time is being expended during real world use, and uses this to tune the optimizer in a second compilation pass. Because it's 64-bit, you are able to use more of your computer's memory for web browsing. You'll notice the difference when you have a lot of tabs open. Not all the plugins work with Waterfox though.