Set General Draw Quality no higher than 8 (9 and 10 will not increase quality, and setting it to 8 may free up enough GPU resources that you can turn on max AA and still get a performance boost if GDQ was set over 8). Full screen mode is faster. Make sure you have the latest windows updates as well as the latest video drivers. Other than the basics, can't offer much until you post your specs and settings in FF (can get both from the FF Config utility).