The Mozilla Foundation has dropped the forth beta of its version 3.0 browser and like we did with the first beta of IE8, we've had a play with this one too. Releasing four betas still seems a little excessive, but Mozilla is always keen to let web developers and other pros play with its new browsers before they hit the streets.

As ever, most improvements are based on user feedback and are behind the scenes, with stability fixes and better compatibility with Windows Vista topping the list. There are also performance improvements, too, and we can report it loads and works very speedily on our single-core Athlon FXpowered machine. It certainly seems a great deal faster than the IE8 beta though remember that is in the extreme early stages of engineering.

One of the notable enhancements is to the Download Manager which has been revamped you can now see where files came from and more easily check on progress of your downloads in the Status Bar at the bottom of your browser window. The browser also has better zooming and magnification a feature Microsoft introduced with IE7. However, so far this isn't implemented in Firefox as well as it is in IE, since you can use a menu in the bottom right of the screen to zoom instead of having to fish out the option from a menu as in Firefox.

Better support for Vista and OS

As for the improved Vista support, the browser has Vista-specific icons hardly enough to set the world alight. There is also better integration with the OS X interface to boot. Elsewhere in terms of the user interface, Location bar and auto-complete results are now returned according to their frecency (a combination of frequency and recency of visits to that page).

The overall impression of Firefox 3 Beta 4.0 is an overwhelmingly positive one indeed it has to be said that fundamentally it seems extremely pacy for a beta, even if it is a fourth attempt. Mozilla claims double speed rendering for Google Mail, as well as 'new technologies' to improve memory usage. Microsoft will have to improve IE8's speed significantly to match it.

You can download the browser now, but don't install it on a critical system though. Feedback about Beta 4 can be entered at www.feedback.mozilla.org or by filing a bug in Bugzilla.