although i'm fairly new to maintaining wine apps, i read that low FPS is (almost) always related to in-game sound changes. i'm not really sure how to alter many settings, but look at some of your sound settings in game and under your wine logs. Apparently, many times when a game has low FPS in wine it's because the in-game music or sound effects are not loading completely right and can cause things like stutters. hope this helps :)
