Au passage, dans la page du tracker de bug :

I've noticed Flash 10.1 has severely degraded performance so the majority of the problems probably had less to do with the Flash hang detection and more to do with people upgrading to Flash 10.1
As an example, Hulu now takes a minute to load videos with Flash 10.1 and uses a whopping 1 GB of memory compared with 256 MB with Flash 10. Even increase the timeout to 45 seconds doesn't always allow Hulu videos to load.

Adobe, de mieux en mieux !