While other browsers are fine, I do find that windowless drawing of 20 ms cycle in Safari is not achievable. I've done up a simple test which shows a small rectangle moving left to right on a 20 ms interval. If compare Safari with other browsers, the rectangle moves slower than the rest. If I set it to 50 ms interval, they then move at the same speed.
Suspecting that this could be inherent in Safari, I tried playing around with youtube (using flash player) they do not show the same problem. I'm quite sure they are in windowless mode as I try to grab the flash plugin's window with SPY++ but found none.
I wonder if anyone has any experience in rendering high frame rate images in Safari.....