以下列出 Beta 3 ->Beta 4 的改進點:
# 新的 download manager
# 整頁縮放
# 和 Vista 的整合
# 和 Mac 的整合
# 和 Linux 的整合
(就是使用原生的布景主題，這樣看起來不會再那麼突兀)
# Location Bar 跟 Toolbar 上面的改善，現在是依據你訪問這個頁面的頻率來做自動完成的部份。(加入自動學習的功能)
# Javascript 變快。
[Improved in Beta 4!] Speed: improvements to our JavaScript engine as well as profile guided optimizations have resulted in significant improvements in performance. 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.
# 記憶體使用量減少
[Improved in Beta 4!] Memory usage: Several 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.
這邊直接從官方下載
