Are you saying it's as unpredictable as C++ performance then? I'll take that ;) I wrote "can" because there are no guarantees, but in practice, this is definit

Are you saying it's as unpredictable as C++ performance then? I'll take that ;) I wrote "can" because there are no guarantees, but in practice, this is definitely done in Firefox and Chrome. See http://www.arewefastyet.com/#machine=11&view=breakdown&suite=asmjs-ubench http://www.arewefastyet.com/#machine=11&view=breakdown&#... - they don't get that close to native speed without such optimizations. Not sure what is going on in IE10, but I am more curious about IE11.