Firefox 5 performance
We ran the trusty SunSpider JavaScript benchmarks on a Sandy Bridge Apple iMac, and Firefox was comfortably ahead: it raced through the benchmarks in 200.4ms, compared to 207.9ms for Chrome 13 and 270.1ms for Safari 5.
Those numbers don't tell the full story, though: the Safari benchmark took ten minutes, with the browser wading through the tests like it was wearing wellies full of treacle, demanding nearly 2GB of RAM and crashing on multiple attempts.
Firefox whizzed through the benchmarks using less than 300MB of RAM, and we haven't seen any signs of catastrophic memory leaks either. That doesn't mean they aren't there, but so far we haven't seen any.
While Firefox isn't a true multi-process browser like Chrome, it does run plug-ins in a separate process, enabling you to kill them if they misbehave without taking all your other tabs down too. That's particularly important on Macs, where Flash has a tendency to fall over.
Firefox 5 extensions
Firefox remains the best browser for tinkerers, control freaks and anybody who wants their browser to be more than a browser. The extraordinary collection of add-ons includes web development tools, scripts to change the way sites behave, tools for various online services and plugins for every imaginable purpose. No other browser comes close.
POWER UP: Firefox remains the most expandable browser around, with add-ons for every conceivable kind of task
Firefox 5 verdict
Let's be honest: if Mozilla hadn't changed its release numbering system Firefox 5 would have been a point release rather than a whole new version. Most of the improvements are for add-on creators and web developers, and there's not much for end-users to get excited about: if you didn't like Firefox 4 you're not going to like Firefox 5 either. Nevertheless it's one of the fastest browsers around, and no other browser can touch it for sheer expandability.
