Q: Help with flash performance

I have a 2009 13 inch macbook pro. Flash performance has been absolutely terrible for me for the last couple of weeks. I can not even play a 480p youtube video without it stuttering. I have figured out that it is not a problem with my bandwidth as I can play HD netflix movies just fine. I recently installed windows 7 professional and flash runs with out a problem. in 1080p on fullscreen mode connected to my 27 inch cinema display. I have tried uninstalling flash, using different versions of flash (11.2 and 11.3 beta) and nothing has worked. Any suggestions will be appreciated greatly. I am running 10.7.4