Hi, I'm experiencing unusually high CPU usage while watching YouTube videos.

The video is running at 2160p and Opera Helper is taking up in the 200-300% range of my CPU according to Opera's Task Manager and Activity Monitor. I'm using YouTube's HTML 5 player.

The same exact video is taxing my CPU at 30% in Safari. It is also running at 2160p and using YouTube's HTML 5 player.
No plug-ins with Opera.

I really want to make the switch, but if this is how it performs with with streaming videos on YouTube, compared with Safari, it's a deal breaker.

Any suggestions or fixes?