If it's dropping frames then you have a network or browser problem I play 1080p youtube videos all the time and never suffer dropped frames ever even in peak times and i never turn off HWA in my browser
I should mention my tests are 4K videos. Probably would be fine at 1080. But I do blame the VP9 hardware acceration because it magically disappears every time I turn it off. Can't be browser/network then, can it?
Edit: I should be clear and mention the drop frames are only a little bit here and there for a 60 FPS 4K video. Still, I prefer zero drops that my CPU is capable of.