Firefox 7 is out. Killer feature? Reduced memory use.

If you’re still on Firefox (Google’s Chrome is now #2 in the UK and some other countries), you’ll be delighted to learn that Mozilla today release Firefox 7, a major new update. Disregarding the obligatory housekeeping, under-the-hood tweaks, optimizations and bug fixes, Firefox 7 drastically reduces memory consumption over its infamous predecessors which have always been criticized for memory leakage problems. This, in turn, has particularly been a pain in the you-know-what on Mac OS X.

Well, according to Mozilla, a non-profit organization behind Firefox, a MemShrink project used in the browser reduces memory use by 20 to 50 percent. As a result, the browser boots faster, your Mac will have more free RAM when skimming through dozens of web sites in Firefox 7 and there’s a lower likelihood of crashing. A Mozilla representative said last week:

Among the Firefox 7 changes are some amazing memory improvements. When this makes it to users in just under 6 weeks, Mozilla will re-take the memory efficiency crown and give our users the highly responsive Firefox they deserve.

Other perks outlined in Mozilla’s blog post include an improved hardware-accelerated Canvas handling which offloads HTML5 animations to your graphics card, making games such as Angry Birds or Runfield run smoother. Firefox 7 also supports W3C’s navigation timing spec, allowing developers to test their page’s load speed remotely. Mozilla also announced the Android mobile version of Firefox which now includes copy and paste.

Firefox 7 is available in more than 70 languages on Mac OS X, Windows and Linux. Grab your copy over at the Firefox download page or wait for the auto-updated mechanism to kick in and prompt you to update your existing Firefox 6 installation. Changelog is after the break.

The latest version of Firefox has the following changes:

• Drastically improved memory handling for certain use cases
• Added a new rendering backend to speed up Canvas operations on Windows systems
• Bookmark and password changes now sync almost instantly when using Firefox Sync
• The ‘http://’ URL prefix is now hidden by default
• Added support for text-overflow: ellipsis
• Added support for the Web Timing specification
• Enhanced support for MathML
• The WebSocket protocol has been updated from version 7 to version 8
• Added an opt-in system for users to send performance data back to Mozilla to improve future versions of Firefox
• Fixed several stability issues
• Fixed several security issues

The complete list of changes is here.