Firefox 4 beta 4 features hardware acceleration ... but will be off by default

Firefox 4 beta 4 is expected to hit download servers on Monday, and this latest build will feature hardware acceleration - although if you want to use it, you'll have to switch it on.

As of today the code for Firefox 4 b4 is described as "mostly frozen" and is on target for release on Monday August 23rd. Amongst the new features such as tab sets, previously known as tab candy (a feature that allows users to group tabs together and handle them as a single entity), is the use of Windows Direct2D to speed up the rendering of text and images on screen. This means that some of the workload will be shifted from the CPU and onto the GPU.

However, this feature won't be switched on by default just yet. Here is a tweet by Mozilla VP of engineering Mike Shaver:

b4 won't have D2D on by default after all; just not quite ready to send it to that many users. soon!

According to Mozilla's planning notes, it wasn't "confident enough to turn it on for all users" just yet.

Switching Direct2D acceleration on and off is pretty easy and just involved a little digging around in the about:config settings:

• To turn on Direct2D: Go in to about:config and set mozilla.widget.render-mode to 6, and gfx.font_rendering.directwrite.enabled to true.
• To turn off Direct2D, once it is on by default, set mozilla.widget.render-mode to 0.
• To check whether you are running with Direct2D, go to about:support and look at the bottom.

It'll be interesting to see how this browser stands up against Microsoft preview platform for IE9 and Google Chrome.