Firefox 4 review

3.5 out of 5


Improved performance with new JavaScript engine (although still not as fast as other browsers), good support for emerging HTML 5 standards, comprehensive sync between devices and hardware acceleration for XP


Panorama tabs are eye candy rather than a useful interface and the improved performance isn’t competitive

The browser wars are hot again, and Firefox is struggling to keep up with the ever updating Chrome and a revitalised Internet Explorer. So it’s about time the open source browser unveiled a new version, with a new look and feel and new features. Firefox 4 has been a long time coming, with the last major version released well over a year ago - in fact that’s longer than it’s taken Microsoft to release IE9. With competition from all sides, has this been a year well spent?

While this is technically version 4 of Firefox, it’s a browser with a long heritage - right back to the early days of the web when it began life as Netscape Navigator; if it used the same version numbering approach as Google’s Chrome this would be at least Firefox 16.

The most obvious change is the new look and feel, which gives Firefox a similar stripped-down look to Internet Explorer or Chrome, with the focus on the content of the page. That’s not surprising, as all three browsers have used automated user research tools to see just what people do in a browser; that’s far more time spent interacting with web pages than digging into settings. So that means that (rather like the other new browsers) there’s a single new Firefox menu, tabs at the top of the screen giving more space for content, and very few icons in the toolbar. One of those is the bookmark button but unlike the IE9 version this doesn’t show you history as well. Unlike most other browsers Firefox still has separate address and search bars, although you can still search in the “awesome” address bar, and that still offers suggestions from your history as you type. One handy new feature; if the history suggestion you want is actually already open in another tab, you can switch to it from this dropdown.

There are also some user interface features that are specific to Firefox, like the new Panorama tab groups, and support for Mozilla’s cloud Sync service.

We’re not entirely sure about the utility of Mozilla’s tab groups - even though we typically have ten or more tabs open. The idea is that you can sort your open tabs into groups, where they’re easier to understand and easier to use, switching between groups as necessary. You get a lot more control than with IE’s automatic grouping of tabs into colour-coded groups when you’ve opened several links from one page, but it’s a lot more work. And while it’s a nice idea, it’s incredibly counter-intuitive, taking you out of your workflow to sort your tabs; they’re always a click away. Most surprisingly there’s no way to save tabs between sessions, leaving the feature toothless, and pretty much useless. The resulting Expose-like “panoramic” overview is pretty, but that’s really all we can say about it.

You can pin tabs for pages you use frequently, but this is much less exciting than the equivalent option in IE9; you can’t drag onto the Windows taskbar or even into the pinned area on the left of the tabbed bar - you can only right-click on a tab to pin it. Even if taskbar pinning only worked in Windows 7 and Vista, it would be nice to see it in those versions of Firefox.

Sync, however, could be the most significant new feature in Firefox 4 because it recognises that few of us browse the web on just one device any more. Building on Mozilla’s experimental Weave project, it lets you store browser bookmarks, settings, forms information and passwords in the cloud (encrypted on Mozilla’s servers) and sync them to all the copies of Firefox you use; that’s far more than the IE Favourites you can sync between Windows PCs with Live Mesh and more than the bookmarks and settings Opera and Chrome can sync as well. Set it up and you can forget about it until you want to load a page or log in to a site you’ve already looked at on another device and it will be right there in your history - that includes mobile Firefox on Android and the Firefox Home iOS application. No more scrolling back through Twitter on your PC to find the tweet with the link you followed on your phone (and no more typing long passwords awkwardly on a phone screen). Unfortunately, useful as Sync is, it’s not the most user friendly of tools, and you’ll need to remember to save your encryption key as you’ll need to use it to set up other devices.

While Firefox 4 is a big improvement from earlier releases in terms of speed, it’s not the fastest browser around, either to start up or to load pages. New JavaScript engines have given its main competitors a significant speed boost, and sadly Firefox continues to lag. We used the Peacekeeper browser benchmark to compare Firefox 4 with Internet Explorer 9 and Chrome 11 - and it came in third across Peacekeeper’s range of tests. Mozilla claims that its new Jaegermonkey JavaScript engine is its fastest yet, and while that may be true, it is still lagging behind Microsoft’s Chakra and Google’s V8. Even on Windows 7 Firefox hardware acceleration was significantly slower than IE9 in our tests; it does give XP the hardware acceleration IE9 doesn’t, but that architectural choice seems to be penalising Windows 7 users - hardware acceleration was noticeably slower in Firefox 4 than in IE9 on our test machine (and yes, we have the up-to-date OpenGL-supporting drivers that Mozilla recommends for getting the best from its hardware acceleration).

Of course speed isn’t all in modern browsers, and to be honest, there’s actually not much difference between the main browsers using tests like SunSpider (real world site speeds differ more and are harder to measure). What’s just as important is support for HMTL 5 and CSS 3, and there Firefox 4 does very well, with the latest version of its Gecko rendering engine offering a wide range of HTML 5 features - including support for the 3D WebGL and for Google’s open WebM video codec (as Mozilla is unable to ship the widely used, hardware-accelerated but proprietary, H.264 codec with Firefox because of its philosophy on licensing). WebGL may become increasingly relevant for 3D on the web, but it is complex for developers to write because they’re working with system-level 3D APIs and primitives rather than a high-level graphics system, so this is more about future-proofing than supporting current sites.

The Do Not Track HTTP header that Firefox introduces won’t make any difference to your online privacy until websites start supporting it. IE9’s system of tracking lists that block and enable specific domains for tracking cookies is more complicated and could be circumvented by ad sites switching to new domains, but at least it offers some immediate protection.

However where Firefox really differentiates itself is in just how much you can customise your browser - with a wide range of third-party tools and extensions that handle everything from link-previews, to ad-blocking, to reskinning the browser just the way you want.


While we do have some quibbles about performance (and we’re more than a little unsure about that bright orange Firefox menu), this is the best Firefox yet. It feels faster, and it’s definitely less bloated. Even so, it’s unlikely to regain its position as our default browser - at least not yet. With Firefox 4 Mozilla is changing the way it numbers and releases browsers to an approach much more like Chrome’s, with a new release every 16 weeks.

These plans for a vastly accelerated development and release schedule are ambitious, but necessary. If Firefox 4 had been launched just a couple of months ago (as originally expected) it would have seemed to be setting the pace for browser development, but coming behind IE9 and Chrome 10, it just seems to be a follower. Stepping up the pace is Mozilla’s only chance of being more than just another browser, and of leaving the browser premier leagues’ relegation zone.