It was not a CPU hog - this is a myth that needs to die The flash runtime was pretty modest.

Now, the code people wrote was CPU hogs, because lots of non coders were writing code and they would do anything to make it work. The Flash runtime was not causing the Punch the Monkey and to peg your CPU, it was because the punch the monkey ad was fucking awful code.

All those Flash programmer went on to write the first wave of HTML5 stuff which, shock horror, where vastly CPU inefficient.