You are not alone. Firefox is unusable for me on my mac book pro 15' 2015. HTML 5 videos are basically a slideshow. On my PC with windows 10, Firefox eat 25% t

You are not alone. Firefox is unusable for me on my mac book pro 15' 2015. HTML 5 videos are basically a slideshow. On my PC with windows 10, Firefox eat 25% to 30% of my CPU looking at a twitch stream (1080p60). Chrome and Edge will use about 5% while looking at the same stream.