The beta contains several performance enhancements:
Enhancements to full-screen mode to use hardware scaling for improved video performance and quality on systems running Windows 2000 and newer or Mac OS X 10.2 and newer.
Faster rendering of vector graphics on multi-core CPUs.
Higher quality and performance for downscaling large bitmaps (SWF 9 only).
Also included in this update:
Support for caching common platform components, such as the Flex framework, to reduce average application sizes. This feature is enabled in the Flex 3 beta available on Adobe Labs.
Support for full-screen mode on Linux.
Recursive calling to and from JavaScript via the ExternalInterface API is now permitted (not available in Opera or Netscape).
Runtime errors can now be thrown from JavaScript to ActionScript via the External Interface API.
HTTP requests from the Flash Player ActiveX Control in some versions of Internet Explorer did not include the Accept-Language header. The ActiveX Control now always inserts this header.
