BYM Lag? Look No Further

#1: Ask yourself this - Am I using Google Chrome? If you're not. Do.
#2: Make sure your version of flash is up to date! DO NOT GO TO THE FLASH WEBSITE THROUGH GOOGLE CHROME. Do this through Internet Explorer. Flash is included in Chrome and it will tell you that it is up to date. It may not be! Download and install it anyways.
#3: Go to your control panel. Find your nVidia/Radeon/whateveryourgraphicscardmightbe settings area. Change them all so that performance is above quality. Play around with it.
#4: Start up chrome. I prefer that my cache/cookies/history/crap is deleted when I exit the window. I don't need that crap. (Settings > Privacy > Content Settings)
#5: When opening BYM, right click on the game window. Change your storage settings to unlimited, and make sure that hardware acceleration is enabled. (You can only do this after you've updated flash)
#6: Read this website. It might help http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager07.html
#7: Do a disc cleanup from the start menu through Accessories > System tools
#8: While on that menu, also do a de-fragmentation of your computer.

Useful Shit:
http://helpx.adobe.com/flash-player/kb/find-version-flash-player.html

Do this:
http://newtriks.com/2012/12/01/how-to-disable-the-chrome-pepper-flash-player/

Follow the steps and disable Pepperflash after installing the real adobe version. Make sure to READ everything. Links are highlighted in blue for you to go to and install flash.