Mozilla released Firefox 3 Beta 5 on Tuesday and reports further performance improvements over the previous prerelease. Beta 4 had already received strong praise in this area. Mozilla says web applications such as Gmail now render twice as fast as under Firefox 2. Other changes focus particularly on operating-system integration. With the full Firefox 3 launch approaching, this may be the final beta.
In mid-March, US technology writer Adrian Kingsley-Hughes praised Firefox 3 Beta 4 for its speed. In a comparison using the SunSpider JavaScript benchmark, the Firefox test version beat its predecessors and competitors from Microsoft and Opera. It also narrowly outperformed the newly released Safari 3.1, advertised by Apple as the fastest browser on any platform. Mozilla says Beta 5 improves SunSpider performance again.
A total of 750 changes from Beta 4 address more than browser speed. Mozilla has further developed operating-system integration, which Mozilla Europe President Tristan Nitot emphasized when Beta 3 appeared. On Windows, Mac OS X, and Linux, Firefox 3 is intended to look and feel like a native application.
Beta 5 may be the final Firefox 3 beta. A code freeze for Release Candidate 1 was expected the following Tuesday. Around the Beta 4 release, Mozilla Corporation Vice President of Engineering Mike Schroepfer said the final Firefox 3 release could arrive in June 2008.