Here is my latest benchmark as solid proof: https://www.dropbox.com/s/58doo8csebp9l62/Bench.pdf?dl=0
Firefox WebGL works much better on Windows for me; never tried it on OS X. It's probably a Linux-specific issue, but I rarely use Firefox on anything else.
It will list HW acceleration info. You want to make sure electrolysis is running, in the line "Multiprocess Windows: 1/1 (Enabled by user)" should be enabled by default, if it says 0/1 it not active and you will have to manually turn it on.
You can also see if the WebGL renderer is loading properly. On my Debian box it says WebGL2 creation failed (drivers), which would explain my poor performance on that box.
It's worth a shot since Firefox's WebGL rendering is 4x faster then other browsers, it's worth your time taking a quick check.