We're planning some more in depth blog posts on how Servo works, and this was already one of the topics I wanted to cover. The gist is that Servo runs most sub

We're planning some more in depth blog posts on how Servo works, and this was already one of the topics I wanted to cover. The gist is that Servo runs most subsystems on separate threads (including sandboxed and cross origin iframes for example), and so each tab or page is not fighting over the same JS engine's time. On top of that, painting/compositing is combined in WebRender and is parallel as well.