Advantages of ActionScript 3.0

ActionScript 3.0 goes beyond the scripting capabilities of previous versions of ActionScript. It is designed to facilitate the creation of highly complex applications with large data sets and object-oriented, reusable code bases. While ActionScript 3.0 is not required for content that runs in Adobe Flash Player, it opens the door to performance improvements that are only available with the AVM2, the new virtual machine. ActionScript 3.0 code can execute up to ten times faster than legacy ActionScript code.
The older version of ActionScript Virtual Machine, AVM1, executes ActionScript 1.0 and ActionScript 2.0 code. AVM1 is supported by Flash Player 9 and 10 for backward compatibility with existing and legacy content.