Why does Adobe Flash Player not work right on my computer after updating?

I've tried to update to version 10.1, 10.2, and now 10.3, but none of them work right. When I try to watch videos in 480p or 720p, it gets choppy and my web browser becomes sluggish until I leave the page or stop the video. I would really like to get a working update because the version I'm running has security issues. What can I do? Any help is greatly appreciated!