Can someone explain to me why ppl think that splitting the browser application into separate processes will positively affect performance?
1. Separate processes for UI and tab rendering/computation. Same reason iOS is always smooth; in addition to allowing faster access to menus, inspector, extensions etc., it simply feels faster to experience an interface at a constant 60fps. 2. Can pass work off to more CPU cores. I'm not sure of the real world performance gain, but theoretically you could render three heavy tabs and the Firefox UI on a 4 processor CP…
Further, most popular modern operating systems handle processes and threads similarly internally.
I'm not sure what you mean by 60 fps. 2d apps typically don't have render loops as games do - they only "composit" graphics typically by updating the UI only if a section needs to be re-drawn.