Firefox 9 delivers "30% speed boost"

Latest version of open-source browser offers improved JavaScript performance

Stewart Mitchell
20 Dec 2011

Mozilla released Firefox 9 today, with the browser update bringing stability and speed improvements.

The update brings improvements in JavaScript, which the open-source developer says offers a 30% speed boost.

The souped-up JavaScript performance relies on a Type Interface tool, which Mozilla says it has been researching for more than a year.

“TI is a feature in the SpiderMonkey Javascript engine which generates type information about Javascript programs through a combination of analysing the program’s code and monitoring the types of values as the program executes,” Firefox engineer Brian Hackett, explained in a blog when the beta was announced last month.

“This type information is used during JIT [just in time] compilation to generate more efficient code; Firefox 9 includes modifications to the JaegerMonkey JIT compiler to use inferred type information," he said.

"This compilation mode, which is the default in Firefox 9, speeds up major benchmarks like Kraken and V8 by over 30%, and gives a large speed boost to many JS heavy websites.”

Alongside Type Interface, Firefox 9 also brings better theme integration and two-finger swipe navigation for Mac OS X Lion, enhanced standards support for HTML5, MathML, and CSS and several bug fixes.

The latest version is available from Mozilla's download centre.

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