One of the major components essential for the future of Firefox just landed in the beta build of the browser, and it gives the open-source browser the page-rendering speed boost that it had been lacking.

Available for Windows, Mac, and Linux, Firefox 4 beta 7 introduces JagerMonkey, Mozilla's next-generation JavaScript engine that puts the browser in the same ballpark as its high-speed competitors. The old TraceMonkey engine was slow enough to no longer be in the same league as Chrome, Opera, Safari, and the Internet Explorer 9 beta.

(Credit: Mozilla, Inc.)

Mozilla describes the improvements as incorporating the JagerMonkey JIT compiler into the new SpiderMonkey engine, and says that users can expect to see significantly faster start-up times, page-load speed, and JavaScript-intensive Web tasks such as running apps and playing games. The company's internal benchmarking shows Firefox 4 is three times faster than the current Firefox 3.6.12 on both Kraken and Sunspider JavaScript benchmarks, and five times faster than Firefox 3.6.12 on the V8 benchmark. Engineer David Mandelin stated in a blog post that Firefox 4 will be "a little bit faster" by the time it's finished.

Although speed is definitely a major part of a successful modern browser, there's more that's changed in the latest Firefox 4 beta besides JavaScript rendering. Firefox was one of the first browsers to incorporate hardware acceleration, and Firefox 4 beta 7 can use your computer's graphics card to load pages faster if the card is supported. The new beta will work on Windows XP, something most other hardware accelerated browsers can't do, and it will work on Macs. The Mac version is powered by OpenGL, while DirectX fuels the Windows version.

Fonts received a boost in this beta, as Firefox 4 now supports the OpenType font format. This will allow designers to control kerning, ligatures, cap variants, and alternative characters. Graphics rendering for developers also got some attention, with the addition of support for 3D graphics rendering via WebGL. Running it currently requires an OpenGL-enabled graphics card, with support planned for other cards in the future.

(Credit: Screenshot by Seth Rosenblatt/CNET)

There's also a nifty about:config tweak that comes in Firefox 4 beta 7. Instead of installing the Bar Tab add-on to better manage Firefox's open session memory, advanced users can go to about:config and set browser.sessionstore.max_concurrent_tabs to 0. This will prevent Firefox from holding in memory all but your most recently-used tabs. Clicking on a tab will automatically refresh it.

The Panorama feature received some small changes, too. It now comes with a "how-to" video that must be manually removed, and there's a dedicated search button that wasn't there before. There's a new button to jump you back to the site you were looking at when you jumped into Panorama, a convenience that was sorely missing from the previous beta.

The speed improvements in this beta are instantly noticeable, but the browser remains in beta and it's not expected to be ready until January 2011. The full changelog for Firefox 4 beta 7 can be read here.