I'm not sure I would call it smooth in Chrome on Windows 7, and this is on a gaming PC (more or less). The process was also using 25% CPU, which I believe Process Explorer would report as one full core.
Not so smooth on Chrome/Ubuntu (on Mac hardware) either.
Cool experiment.
Not smooth at all when you scroll.
It plays nicely on iPhone 2G but scrolling and zooming make it hang for a while, I even made the animation stop somehow.
I'm not sure this is the way to go...
Also on an iPhone 3G. Text is small, but the animation smooth and not slower than on my Macbook.