I ran your box benchmark at 1000 boxes and all browsers were able to sustain 60fps quite easily on my system.
Firefox, Chromium, Chrome, Safari and Opera on OSX
Firefox, Chromium, Chrome, Safari and Opera on OSX
On MY system chrome is still quite ahead of FF. And that was the point, not that you have a good pc ...
(oh and the benchmark is not from me, but actually from the FF dev team itself, as part of emscripten ... and they used to be quite faster than all the others, but apparently not anymore. At least not at the moment ...)