Yah and that's why I included 3 very real world heavy benchmarks that run random multiple real world usage patterns for extended periods of time. An those were the benchmarks that Firefox pulled a head of the pack by a large margin. The basic Java Benchmarks like Sunspider and Ocatane that useless tech sites use to compare the browsers test nothing more then the Java engines of the browsers, pushing numbers while omitting the browsers respected renderers completely.

If we are comparing Chromiums V8 Java engine vs Firefox's Spidermonkey then Chromiums V8 is faster, but would you even be able to tell the difference?

Now day to day usability I am forced to use Firefox because I'm a tab whore and constantly run 80 tabs at all times. When I try doing that with other browsers they choke within an hour to up-to 2 days. Firefox allows me to run ~80 tabs with up-times approaching 2 months regularly. But that's the way I use my browser, other people would care about other features more.

Now of coarse different builds on different OS's you will run into different problems. On my Debian stable box, Firefox doesn't play nice and I'm forced to use Chromium, but on Ubuntu, Firefox performs solid. Now the main reason Firefox is running like ass on some systems is due to having old extensions installed, which forces Firefox to drop HW acceleration and fall back into compatibility mode. The Problem on my Debian box is that Firefox is not loading the WebGL2 drivers (gives me a bad driver error), thus HW acceleration is broken and it runs like ass.

You can confirm this on your install by typing in "about:support" in the address bar. If you are running 51.0.1 you can see if Electrolysis is enabled by looking at the line "Multiprocess Windows 1/1 (Enabled by user)" if yours reports "0/1 (Disabled)" then a shitty extension is forcing it in compatibility mode. You can manually force it on and type "about:performance" to see what extension is the culprit.

Also in "about:support" take a look at the Graphics table, your Compositing should be OpenGL and your WebGL renders should be the name of your GPU without a reported error. You can also "refresh" Firefox at the top right of the page, but if you can't get HW acceleration in FF then use Chromium of coarse, but if you can solve the problem quickly you will have another powerful tool to tackle the web and I'd like to know how it Performs in Arch.

Plus, since you are working with WebGL content it would be great to get Firefox working, cause at the moment Firefox is almost 4x as fast as Chromium on WebGL2 Unity3D.