@why9,
I'm using the current version of Firefox (20.0) with Flash Player version 10.3.183.48. The new version of Flash Player (11.xx) has a protected mode built into it and it's suggested to set it's parameters to 0/false, but in many instances, this doesn't correct the choppiness that occurs with Flash platform web sites.
Reverting back to an older version of Flash Player is recommended by Adobe.
What optimization tasks are you doing for WGT game-play?
What OS are you using?
What version of Flash Player did you switch to?
You have to be sure to uninstall the the old Flash Player before installing the new one. You'll only need to run the Flash Player for Windows. There's no need to extract all the Flash Player versions in the 10.3.xxx.xx Flash Player download.
I would suggest using a different browser and not use IE or Chrome for WGT game-play. They tend to be a pain in the rear. Some players have good luck with those browsers, but most don't. I would suggest Firefox, Palemoon, or Maxthon browsers.