Mozilla is in the process of pushing Firefox 9 out to users on its release channel, about six weeks after the release of Firefox 8. The major stated improvement to Firefox 9 is what Mozilla calls the Type Inference for JavaScript, which it says improves performance up to 30 percent in some benchmarks. To test this, I ran a few quick SunSpider tests to compare performance to older versions of Firefox and current versions of Chrome and Safari. These tests were run on a 2010 iMac running OS X 10.7.2 with all updates installed and are only meant to measure relative performance between browsers running on the same computer.

Update: We've also run Kraken 1.1 and the v8 Benchmark Suite version 6 on the same browsers - these numbers come a bit closer to realizing the 30 percent improvement over version 8, while even more conclusively demonstrating how far Firefox has come since version 3.6.

SunSpider 0.9.1 JavaScript Performance

v8 Benchmark Suite, Version 6

Kraken JavaScript Benchmark 1.1

In a standard SunSpider run, Firefox 9 is consistently faster than Firefox 8, but not by anywhere near 30 percent (bearing in mind, of course, that this is just one synthetic benchmark among many). Also note that JavaScript numbers are just one facet of performance - while Safari edges out Firefox 9, to me it seemed a bit slower than both Firefox and Chrome when launching and loading pages. All current browsers completely wipe the floor with Firefox 3.6, both in JavaScript numbers and in apparent speed, so whatever you use you're going to be browsing much faster than you could at the beginning of the year. Increased competition has clearly been good for the browser market.

Firefox 9 also brings two-finger navigation to users running OS X Lion - swiping left on a multitouch device will go back, and swiping right will go forward. Safari and Chrome have already implemented this feature, and while the functionality is the same in Firefox, those browsers include visual cues (arrows in Chrome, a visual sliding of the page in Safari) to let you know that you're doing it, visual feedback that I find helpful. There's still no support for fullscreen mode, though plugins exist to give this functionality to those who want it.

The rest of the improvements can be found in the usual laundry list of small security and bug fixes (including one I had run into where attachments wouldn't download properly when using the Outlook Web App - useful information for shops running an Exchange server). You can get the new browser by using Firefox's built-in updater or by visiting

Note: At the moment, Mozilla says that it's not pushing Firefox 9 out to OS X and Linux users automatically because of "a possible issue affecting a small number of users." We'll keep an eye on this and update the post as events progress.

Source: Mozilla

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  • arjuna1 - Wednesday, December 21, 2011 - link

    Mozilla Nightly gets x64 builds and daily updates.
  • Andrew.a.cunningham - Wednesday, December 21, 2011 - link

    Which is awesome! And I'm looking forward to 64-bit browsers becoming commonplace now that 64-bit Flash finally exists.

    However, most people need something more reliable and stable than nightly builds - you and I are probably comfortable working around any inconveniences that pop up, but that doesn't cover everyone. Enough people are up in arms about the new rapid update process as it is.
  • arjuna1 - Wednesday, December 21, 2011 - link

    one of the nicest replies from AT staff I've seen, keep it up!
  • Andrew.a.cunningham - Wednesday, December 21, 2011 - link

    Sure thing! Thanks for reading!
  • GTVic - Thursday, December 22, 2011 - link

    What does a 64-bit browser have to do with 64-bit flash?
  • GTVic - Thursday, December 22, 2011 - link

    Never mind, thought you were talking about flash memory.
  • tipoo - Wednesday, December 21, 2011 - link

    Palemoon has stable 64 bit versions of Firefox. Its just Firefox recompiled for newer instruction sets like SSE2 and optional 64 bit. No reason not to use it IMO, its just as stable as Firefox stable 32 bit.
  • arjuna1 - Wednesday, December 21, 2011 - link

    Honestly, I've yet to have a single problem with Nightly x64, apart from last night when I had to kill the process, but then again, that's one occasion against the countless times I have had to do that with Firefox.

    Hopefully at some point in time Palemoon's improvements will be integrated into the main sources .
  • tipoo - Wednesday, December 21, 2011 - link

    I hope so too. They are slowing down how fast it could be to appease the single digit percentage of their install base without processors with more modern instructions, there's a time you just have to say this is the cut off like for older systems, and forge ahead. SSE2 isn't even that new, I hope Firefox goes with the newer instruction sets and Palemoon goes with the latest ones like 4.1, 4.2, 5, and whatever else is out by then.
  • DanNeely - Wednesday, December 21, 2011 - link

    How hard are you using your browser? Most of the people I know with FF32 issues are using dozens to hundreds of open tabs; and large numbers of extensions (or ones like Firebug that leak badly).

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