That's weird, I use Mac (x86) and Linux (x86 Debian) and Firefox works great on Linux but is unusable on Mac (at least it was two or so years ago when I last tried).
I have an nvidia card and non free drivers if that matters
>>sbaidd+(OP)
Firefox has improved a lot on mac in the last two years. It's still less battery efficient than Chrome, but not by too much anymore. I've just switch for it's better tab management features (tab groups).