The full release notes can be found here: rich Internet applications | Adobe Flash Player featuresStage Video hardware acceleration New (in Flash Player 10.2)
Leverage complete hardware acceleration of the video rendering pipeline with this new method for video playback. Dramatically decrease processor usage and enable higher frame rates, reduced memory usage, and greater pixel fidelity for best-in-class high-definition (HD) playback performance.
Internet Explorer 9 hardware accelerated rendering support New (in Flash Player 10.2, desktop only)
Take advantage of hardware accelerated graphics in Internet Explorer 9 with Flash Player, utilizing hardware rendering surfaces to improve graphics performance and enable seamless composition.
Native custom mouse cursors New (in Flash Player 10.2)
Define custom native mouse cursors to enable user experience enhancements and improved performance.
Support for full screen mode with multiple monitors New (in Flash Player 10.2, desktop only)
Keep content in full-screen mode on multiple monitors, allowing you to see full-screen content while working on another display.
Sub-pixel text rendering Enhanced (in Flash Player 10.2)
Experience improved readability of text in Flash Player, especially for complex character-based languages.
Fast switch Enhanced
Show exceptional video with streams that automatically adjust to changing network conditions. Leverage new quality-of-service metrics to provide a better streaming experience. Flash Player is enhanced to improve switching times between bitrates.