1. Start the game. Do stuff until the fps cycling starts.
2. command-tab out of the game. let it sit for 10 to 15 seconds, then go back to the game.
3. If the fps has stabilized, continue playing. It will probably start cycling again soon.
4. If not, then repeat step 2.
5. When the cycling starts again, repeat steps 2 to 4.
In my experience, after three or four repetitions of the above steps, the cycling fps stops, not to return until the next time the game is played.