If there were three words to describe Mozilla's biggest concerns with the mobile version of its browser, they would be: speed, speed, and speed. The company released today Firefox Mobile 4 beta 5 for Android 2.1 and higher and Maemo with no major new features or feature improvements, instead choosing to make this release about improving the browser's performance.

Mozilla is claiming noticeable improvements in start-up speed, page load speed, and JavaScript rendering speed. The company also said in its Firefox 4 Mobile beta 5 release notes that it intends to continue to focus on "reducing memory and optimizing CPU usage." To that end, it specifically calls out its key Sync feature as one area ripe for improvement.

Firefox 4 beta 5 on Android is actually slightly smaller than the fourth beta (see slideshow), clocking in at 13.5MB as compared with 13.7MB last time. The size of Firefox on your phone will continue to be large because it uses its own JavaScript and rendering engines, separate from the default browser. To help users on older Android-using hardware, the browser will now migrate its profile data to the SD card when the application itself is moved to the SD card on Android 2.2 or higher.

In brief hands-on use on a Dell Streak 5 running Android 2.2, the browser felt snappy. Using multiple add-ons didn't feel like it slowed down the browser, either, perhaps a sign that add-on integration has matured in this beta. There's not much else to this version of the browser, so please let us know what you think of Firefox for Android in the comments below.