Firefox 3 Beta 4 is ready for download. Well there was some confusion yesterday on if it was out or not, so I decided to hold off on this till today. Yet again, Mozilla continues to surprise and amaze with improvements to the core product. Two of the biggest updates I would say would be:

• Speed:
  Improvements to our JavaScript engine as well as profile guided optimizations have resulted in significant improvements. Compared to Firefox 2, web applications like Google Mail and Zoho Office run twice as fast in Firefox 3 Beta 4, and the popular SunSpider test from Apple shows improvements over previous releases.
• Memory usage:
  Some new technologies work together to reduce the amount of memory used by Firefox 3 Beta 4 over a web browsing session. Memory cycles are broken and collected by an automated cycle collector, a new memory allocator reduces fragmentation, hundreds of leaks have been fixed, and caching strategies have been tuned.

You can check out the full list of improvements and updates on the release notes and as always, Mozilla Links has an awesome in-depth review of this newest Firefox beta release.