Mozilla hopes to release its fourth beta of Firefox 4 on Monday, adding hardware-accelerated graphics for some Windows users but leaving it turned off by default.
Also coming is a major user interface change called tab sets, formerly known as tab candy.
Hardware acceleration, coming to all the major browsers in various forms, is designed to shift some tasks from a computer's main processor to its graphics processor. One way Firefox is tackling the technology is by using Windows' Direct2D interface, which can speed up the display of text and graphics on newer versions of Windows.
Mozilla planners had hoped to enable Direct2D in the fourth beta, but decided caution was appropriate. "b4 won't have D2D on by default after all; just not quite ready to send it to that many users. soon!" tweeted Mike Shaver, Mozilla's vice president of engineering.
Firefox 4 is designed to be faster and better so Mozilla's browser can compete better as Google Chrome matures and as Microsoft's Internet Explorer reverses its usage-share slide and gets a major overhaul. Faster display is crucial in the performance race.
Faster browsers can enliven use of the Web, not just for loading sites but also for using Web applications or otherwise interacting. Mozilla and Microsoft have been in a bit of a competition to add support for the feature, which made a splashy debut in "platform preview" versions of Internet Explorer 9.
Even though Direct2D rendering won't be activated by default, Mozilla hopes people will test it. Here are Mozilla's instructions for enabling Direct2D in Firefox by changing settings accessed by typing "about:config" into the address bar:
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 [in the address bar] and look at the bottom.
Speed isn't the only factor, of course. As people spend more time in browsers, though, it gets harder to manage all the different tasks running simultaneously. For this reason Mozilla developed tab candy. It will appear in Firefox 4 beta 4 with the less tasty but more descriptive "tab sets" name.
Tab sets let people group tabs into bunches and move them around for what Mozilla hopes will be easier management than just using multiple browser windows, each with a linear strip of tabs across the top.
Another change that already arrived in Firefox 4 beta 3 is a feature called "switch to tab," which can move a person to an open tab when they start typing it into the address bar. It makes it easier to locate specific Web pages amid the tab clutter, but makes it harder to open duplicate pages of the same site.
A third tab change that's already in the Firefox betas is app tabs, which let people shrink a regular tab into a narrow icon to the left of the tab strip. It saves real estate in the tab strip and helps organize tabs by task.
The next version, Firefox 4 beta 5, is scheduled to be the last with any new browser features, according to Mozilla planning notes that mention that "feature freeze."
"There's a lot of things to go in it," the notes say. Mozilla programmers hope to freeze the code at the end of August, a step that shifts developer attention to fixing necessary bugs rather than adding anything new.