When we look back over the history of web performance we see a heavy focus on reducing the number of requests and getting files to the browser quickly. Our platform has changed a lot, and while optimizing for network performance remains a crucial part of our jobs, we now have to broaden our performance horizons. Our users also expect smooth scrolling, animations and interactions, even on mobile devices. In short we need to deal with not just how quickly our sites and apps load, but also how quickly they run. More info at: https://fronteers.nl/congres/2013/sessions/rendering-performance