GPU accelerated Flash... not so fast Mac, you too Linux.

The beta is available for Mac, but no hardware acceleration.  Windows only for now:
http://labs.adobe.com/technologies/flashplayer10/

From the Hardware requirements section:
http://www.adobe.com/devnet/flashplayer/articles/fplayer10.1_hardware_acceleration.html

Linux and Mac OS X hardware-accelerated decoding is not supported in this version.