The firefox4-4.0-0.19.beta10 package install this new version besides the version 3.x. So you will have 2 entries in the Internet menu.

Start by reading :

As always :

yum --enablerepo=remi install firefox4

If you prefer to replace the system firefox, with fedora >= 12, you can also install firefox-4.0-0.19.beta10 from remi-test repository.

yum remove firefox4
yum --enablerepo=remi-test update firefox

No xulrunner update, this RPM provides his bundled Gecko engine.

The Add-on compatibility reporter 0.7 allow to enable extension which are not compatible for test.

Some benchmark results:

  V8
More is better		 SunSpider
 Less is better		 Kraken
 Less is better
Firefox 3.6.10 382 1 469.4 ms 61 796.7 ms
Firefox 3.6.13 394
 1 435.3 ms 60 490.3 ms
Firefox 4.0b7 4 010
 241.7 ms 5 278.1 ms
Firefox 4.0b8 4 634
 236.8 ms 5 221.3 ms
Firefox 4.0b9 5 158
 218.5 ms 5 143.7 ms
Firefox 4.0b10 5 099
 225.8 ms 4 712.3 ms

Tests run on:

Fedora release 14 (Laughlin)
Intel(R) Core(TM) i5 CPU 760 @ 2.80GHz