Earlier today, Mozilla quietly made available the Beta 1 build of Firefox 4 on its FTP server. The company has not posted any release notes or made any announcements. At least, not yet. Anyway, considering it’s just a beta 1 build, the browser currently contains several issues. In other words, Firefox 4 Beta 1 build should not be used as a default browser, as it will cause users some headaches. That’s probably the reason why Mozilla is not going public with it.

According to the SunSpider Benchmark, the current Firefox 4 Beta 1 build is still way behind its competitor, as demonstrated in the graph below by ConceivablyTech. Even the preview version of Internet Explorer 9 managed to do better, and we can expect it to improve toward the final release. However, the leadership is claimed by Google Chrome, which is close to breaking the 300 ms mark.

Download Firfox 4 Beta 1

Do take into account that you might encounter many bugs.