If you’re anxiously waiting for the arrival of Firefox 3.1, you may want to sit tight. While the 3.1b2 is now available in the nightly builds, you probably don’t need to make the jump just yet – unless you’re looking for speedier javascript processing.

The changes that are included are a good start, and bode well for the final release of 3.1. The improved ctrl+tab switching looks and functions well, and the new TraceMonkey javascript engine provides a nice performance boost. You’ll have to activate it yourself by opening about:config and setting the javascript.options.jit.content boolean to true.

A quick comparison on acid3.acidtests.org revealed a score of 90 in 3.1b2 versus a 71 in 3.0.3 – a gain of about about 27%. Not too shabby!

Also included in the build is the geolocation function Mozilla introduced with the previously reviewed Geode addon, which simplifies the delivery of location-specific web content.

Notably absent from the build are the highly anticipated private browsing feature (can we please stop calling it “porn mode”?) and smart session restore. If you’re waiting for them, you’ll have to be patient a bit longer. On a good note, none of my addons failed to work after installing the upgrade.

Betaphiles, stay tuned to the nightly builds on Mozilla’s FTP server for the latest releases.