This guide is a little how-to for enabling the hardware acceleration in Firefox, when we use Ubuntu. I never test it under other Linux O.S., but I hope it functions anyway.
First of all open Firefox and type in “about:config” in the address bar. In this section search: “layers.acceleration.force-enabled” and set it true. Do the same with the “layers.offmainthreadcomposition.enabled“.
Done this go to the home folder, and show the hidden files (by ctrl+h), and open “.profile“. In the end of this file attach this: “export env MOZ_USE_OMTC=1“, then save and close.
Now try to logout and login back and go to “about:support” and, at the middle of the page, under the graphic section you can see the line “GPU Accelerated Windows” and, it all it is going right you will see 1/1 of your accelerated window.
I tested it under Ubuntu 14.04 with Firefox 31/31 and the last Nvidia driver, I hope this post can be useful.