On Linux, Firefox hardware acceleration is disabled by default on all distributions. The reason is about a potential security risk or a faulty implementation that does not properly support dual-GPU systems, or something more.
So, first of all, read carefully this post on Reddit, the potential security problem due to WebGL and about the Firefox hardware accelerated rendering on X11. After that, you can try to transform Firefox in a super fast web browser.
Enable hardware acceleration in Firefox
To enable hardware acceleration in Firefox on Linux, we must enter in the advance configuration menu of the browser.
In the Firefox address bar, type this:
layers.acceleration.force-enabled and double click on it to turn the value from ‘false’ to ‘true’.
Finally, restart the browser and enjoy its new speed. Personally, I did it on my testing machine with Fedora 26 Alpha and Firefox 53 on board, and I found it really faster, especially with a lot of tabs opened.