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Firefox 9 delivers "30% speed boost"


By Stewart Mitchell

Posted on 20 Dec 2011 at 11:35

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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User comments

"Inference" not "Interface"?

Two instances. Also "tool" is odd, looks more like an "algorithm" or an "engine". A "tool" is normally used manually in specific circumstances not as part of an automatic process.

By JohnAHind on 20 Dec 2011

Start-up time...

And the start-up time still takes 10 secs. When will they sort this out, Chrome loads in under 2 secs.

By treadmill on 20 Dec 2011

Once a day...

As the browser is generally started once a day, what does the startup time really matter? On old work PC (Core i5 1st generation), it takes around 2 seconds to load, on my 2 year old laptop, it takes around 2.5 seconds to load.

It is the same as boot times. By the time I've switched the PC on and gone to put the coffee on, the PC has been waiting several minutes for me to log in. :-D

By big_D on 20 Dec 2011

big_D is right..

and that includes his own startup times. If it's taking 10 seconds to start, I don't think it's Firefox - probably one of the add-ons.

I've just tried it but it refused to start up at all - uninstalled and re-installed the previous versions and it works fine. I'll wait for the official launch ;)

By artiss on 20 Dec 2011

I am not going to be as dogmatic as to pronounce big_D right. I have just started both up and although nothing probably is going to beat Chrome, they are so close as makes no difference.

As for starting a browser once a day - NO Way José! Chrome seems to collect new processes like my girlfriend hoards shoes. It is nice to shut it down regularly to clear the memory out. Also, if I am leaving the PC running when I leave it, I don't particularly want my CPU running a page of animated ads for no reason.

I have done a brave thing [for me]. I have made it my default browser over Chrome today and see how easy it really is to live with. If I am still using it in 3 days then it probably is fast.

I am only running 'firebug', 'SEO professional' and 'tab mix pro' as add-ons. All the others are perpetually out of date.

By Alperian on 20 Dec 2011


I use FlashBlocker on Chrome and Firefox and ClickToFlash on Safari.

They block all flash content, replacing it with a white frame and a "play" button. Only after the play button has been clicked does the flash content load.

That means no annoying adverts and I can have my 30 - 40 tabs open, wihtout it being a big drain on resources.

I also use NoScript in Firefox, which stops unknown / untrusted sites from running JavaScript - for example of the 14 domains trying to run scripts on this page, only 3 are enabled.

By big_D on 21 Dec 2011

"although nothing probably is going to beat Chrome, they are so close as makes no difference"

I'm finding not much difference.

Firefox is now no longer sluggish and (at times) "not responding". Fingers crossed that this continues.

By Lacrobat on 21 Dec 2011


Do you really think I'm being dogmatic by agreeing with Big_D? Not at all - I disagree with many of the things he says, which is why when I do it's worth mentioning ;)

I've tried Chrome in the past but don't like the method of searching. Yes, a small thing, but I like the dedicated search box in the corner!

By artiss on 23 Dec 2011

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