According to quick tests run by Computerworld using the SunSpider JavaScript benchmark suite, Firefox 4 Beta 8 is about 5% faster than its forerunner.

Mozilla had previously added other major features to Firefox 4, ranging from a new JavaScript JIT (Just In Time) compiler, dubbed "JagerMonkey," in Beta 7; hardware acceleration in Beta 5 last September; and a new tab manager, dubbed "Panorama," in Beta 4 a month earlier.

Alongside Beta 8 for Windows, Mac OS X and Linux, Mozilla today also issued an updated beta of its mobile browser, which runs on Android-powered smartphones. Changes in the mobile edition of Firefox were more noticeable, and included revisions to the user interface, changes to the add-on discovery process, and like its desktop cousin, streamlined Firefox Sync setup.

can be downloaded for Windows, Mac OS X and Linux from Mozilla's site.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at , or subscribe to . His e-mail address is .