"Like all of the graphics in IE9, canvas is hardware accelerated through Windows and the GPU. Hardware accelerated canvas support in IE9 illustrates the power of native HTML5 in a browser." [1]
They have a demo linked on that page where I get 1 fps when I run in it chrome. Their screenshot of IE9 running the demo shows 60 fps. I suppose hardware can make a difference, but thats its a really impressive.