While Mozilla was promising to release version 9 of its Firefox browser tomorrow, the official download links are live now.

Huge performance changes have been made in this release, while there aren’t any user interface changes that you’ll notice.

The double-digit increases in performance that most are reporting come from a new feature called “type inference”, created by Mozilla developer Brian Hackett. The feature now quickly chooses how to handle JavaScript, which doesn’t require a developer to define a variable. That makes the browser work overtime, but with type inference, the difference in performance is definitely noticeable.

Firefox 520x270 Download Firefox 9 a day early and enjoy a 20% 30% increase in performance

Here are the rest of the changes and updates that come with version 9 of Firefox:

Added Type Inference, significantly improving JavaScript performance
Improved theme integration for Mac OS X Lion
Added two finger swipe navigation for Mac OS X Lion
Added support for querying Do Not Track status via JavaScript
Added support for font-stretch
Improved support for text-overflow
Improved standards support for HTML5, MathML, and CSS
Fixed several stability issues

You can download Firefox 9 for Mac, Windows, and Linux now.