before the main gets messed up... how many wows are you running and what is the size and fps for each one? (hit ctrl+R to show the fps)

ie:
wow1 800x600 40 fps
wow2 400x300 10 fps
wow3 400x300 10 fps
wow4 400x300 10 fps

then... after a few pip swaps and the fps seems messed up... do the same