It's also 14.5 percent faster than Firefox 3.5, the Mozilla browser that debuted in June 2009, a slightly larger speed increase than Mozilla has claimed.
Safari edged Chrome for first place in the speed race, beating Google 's browser by about 6.5 percent, a slightly smaller lead than in a November time trial that pitted Mac versions of the browsers against each other.
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.
Microsoft has not yet unveiled a test or preview build of IE9 that can be independently tested, however.
Mozilla made other changes to Firefox 3.6 to speed up the browser.
The Mac edition starts up about 30 percent 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 company claimed 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 Acid3 benchmark 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.
Firefox currently accounts for about 25 percent of all browsers used worldwide, according to the most recent data from web metrics company Net Applications.
With a quarter of the browser market, Firefox is a distant second to IE's 63 percent, but enjoys a huge cushion over the current number three browser, Chrome, which has a 5 percent share.
See also: Mozilla kills Firefox 3.7