Firefox 4 Full, ready to upgrade?

If you are a current Firefox user, the decision to update really is a no brainer. For Mozilla, the question is whether this major release will help it maintain and grow its web browser market share. It's a question that will be answered by more than just fancy user interfaces, that is, in the underlying technology used to render websites.

firefox4-1For Mozilla, completing Firefox 4 can't come soon enough. In the last two years it has taken some hits from Apple's Safari, Google's Chrome and recently even Microsoft's Internet Explorer 9. Google in particular has gone down the route of almost constant beta updating backed up by an advertising campaign, which has seen it enjoy some market share growth at the bleeding edge.

It isn't the growth of Firefox's rivals that got Mozilla worried, but rather the sense that Firefox had grown bloated and slow that would have got alarm bells ringing. On first impressions it looks like Mozilla has listened.

With a prolonged beta testing period, it was clear that when Firefox 4 did finally arrive there wouldn't be too many surprises. By the time Mozilla released the 12th and final beta, Firefox 4 had a polish about it that many software firms would find hard to achieve after a year of production patches and updates. The long beta cycle was a good idea, as Mozilla released a new version of the Gecko rendering engine and an updated Javascript engine called Jaegermonkey.

What users will notice first is the relocation of tabs from below the URL bar to above it, however in reality that is the most unimportant change of all, because it is Jaegermonkey that holds the key to Firefox's success. Coding purists might view Javascipt with disdain, but the truth is that the performance of a web browser's Javascript engine is vital to the overall user experience and, on that front, Mozilla has made significant strides.

Benchmarking Firefox 4 against Firefox 3.6.12 on a 2.66GHz Intel Core 2 Duo E6750, the Spidermonkey Javascript benchmark was completed in 277.3ms on Firefox 4. Compare this to 839.4ms on Firefox 3.6.12 and you start to realise that Mozilla hasn't spent the last two years simply working on the eye candy aspects of the Firefox 4 user interface.

Aside from Jaegermonkey, Mozilla's Gecko 2.0 engine improves support for HTML5, CSS3 and WebM. Firefox 4 has had hardware acceleration since its fourth beta release, however it still supports only Windows 7. That's a big disappointment for a web browser that is bundled with almost every Linux distribution.