Even Microsoft, which had disparaged speed tests, has acknowledged its developers are working on giving the next version of IE a kick in the pants. In November, Steven Sinofsky, Microsoft's president of Windows and Windows Live, claimed that early work on IE9 put the browser's JavaScript speed "on par" with rivals. Microsoft has not yet unveiled a test or preview build of IE9 that can be independently tested, however.

David Mandelin, who works on Mozilla's JavaScript team, has posted technical details on Firefox 3.6's JavaScript improvements on the .

Mozilla made other changes to Firefox 3.6 to speed up the browser. The Mac edition starts up about 30% faster than Firefox 3.5, for example, while changes to the location bar -- the searchable address bar that Mozilla dubs the "Awesomebar" -- on all versions have resulted in what the were "massive improvements in [user interface] responsiveness when typing in the location bar."

On another oft-quoted scoring system, the final of Firefox 3.6 did not budge from earlier beta builds of the browser, however. As it had last year during its beta testing, the production version of Firefox 3.6 scored 92 out of a possible 100 on the , which checks how closely a browser follows standards related to DOM (Document Object Model), CSS2 (Cascading Style Sheets) and SVG (Scalable Vector Graphics).

Current editions of Safari, Chrome and Opera all score 100 on the Acid3 test, while IE8 reaches only 24.