Super Speed
Fasten your seatbelt: Firefox now includes the TraceMonkey JavaScript engine, which gives the browser dramatically better performance than ever before. Firefox has always been fast, but this is the fastest Firefox ever (more than three times as fast as Firefox 3 and 20% faster than Firefox 3.5), meaning Web applications like email, photo sites, online word processors and more will feel snappier and more responsive.
Faster Page Load
A redesigned page rendering and layout engine means you see Web pages faster—and in the way they were meant to be seen.
Real World Performance
Having a super fast JavaScript engine is definitely important, but since those changes are often measured in milliseconds sometimes what matters even more is the way the browser feels when you’re actually using it. That’s why we’re constantly optimizing Firefox to be great for the way you use the web – things like making new tabs open up more quickly, or having the Awesome Bar provide results even faster. In the end, it’s about getting you where you need to go as quickly and easily as possible.
Memory Management
With a new management function in place, Firefox keeps memory usage under control. The XPCOM cycle collector continuously cleans up unused memory. Plus, hundreds of memory leaks have been remedied.
Crash Protection
Firefox provides uninterrupted browsing for Windows and Linux users when there is a crash in the Adobe Flash, Apple Quicktime or Microsoft Silverlight plugins. If one of these commonly-used plugins crashes or freezes, it won't affect the rest of Firefox. Instead, you can simply reload the page to restart the plugin and try again.
