It's not really using 100%. rAF means they do their work, then it goes to sleep until the next vblank. They then get their rAF event, check if they want to make

It's not really using 100%. rAF means they do their work, then it goes to sleep until the next vblank. They then get their rAF event, check if they want to make any changes to the DOM, queue another rAF and then go back to sleep. So it really is only 10-20%. But it's still 10-20% :-( I would be curious why it's at 10-20% though. If they don't touch the DOM and their checks are quick (just a pointer as the article says) then there's some crazy serious overhead in the browser or somewhere just to call into JS once every 16-17ms and have it go back to sleep. It would be interesting to look into where 10-20% is going. It seems like in a perfect impl, a mostly no-op rAF should take 0.001% or something along those lines.