If you don’t already have Ubuntu Tweak I recommend it. From there you can enable the development repos for Firefox development versions. Under Applications>Third-Party Sources. Otherwise you can do it strait from launchpad.
If you run the update manager Firefox 3.5.6pre will be installed, and Under Synaptic Firefox 3.6b3 and 3.7a1 will be available to install. I only tried installing 3.6. It wont overwrite your current install of FF, and I noticed I could even run two versions at the same time. In the applications menu “Firefox” will be replaced with Shiretoko (the code name for the 3.5 release) and Namoroka (the code name for 3.6) will now show up.
There are other more complete browser benchmarks out there, but I just wanted a quick rundown of how much of a performance improvement is coming with 3.6.
Ubuntu 9.10 – Nov 12th 2009 – Sunspider:
Epiphany 2.28 [w/WebKit] (64bit) – 580.2ms
Chromium 126.96.36.199 (64bit) – 583.2ms
Chromium 188.8.131.52 (on slower 32 bit system) – 616.2ms
Epiphany 2.28 [w/WebKit] (on slower 32 bit system) – 954.8ms
Firefox 3.6b3pre (on slower 32 bit system) – 1385.4ms
FF 3.5.5 (on slower 32 bit system) – 1642.8ms
Firefox 3.5.6pre (on slower 32 bit system) – 1677.0ms
Firefox 3.6b3pre (64bit) – 2084.2ms
Firefox 3.5.6pre (64bit) – 2755.8ms
Opera 10.01 (64bit) – 3701.4ms
Opera 10.01 (on slower 32 bit system) – 6089.0ms (yikes!)
For whatever reason FF does poorly on the sunspider test on my 64 bit machine. I switched this machine to 64 bit when I did a fresh install of Karmic. I have run previous tests on in it as 32bit and FF did better then. see old post. Surprisingly Epiphany won the race overall.
That inspired me to play with Epiphany just a bit and found out it can be customized to be a pretty slick browser! I found it has an inspector for web developers, automatically opens source (ctrl+U) in gedit, and in many way behaves very much like chrome. It opens fast, plays flash well, and the chrome can be stripped down so it wastes less screen space. For example if you turn off the status bar link URL’s show up in the bottom left corner just like in Chrome, a nice little touch. The unified address/search bar also serves as a progress bar like Safari used to/does(?). here’s a screenshot: