From my recent experiments with frame rate on browsers, I found that the so-called magic frame rate of 31fps doesn't actually work for me (maybe at one point it did). On my machine, if I publish my movie at 30fps, I get about 22fps on IE. Publishing it at 40, I get about 32. Beyond 40, the frame rate actually goes down. So make sure to check your actual browser's fps. They don't behave the same way as a Flash player (or in test movie) would. It certainly doesn't make sense to publish your movie at 60fps and hope the browser would push the fps toward that rate.