If your system isn't getting 36 fps, use these settings to work towards getting the frame rate around 36 fps. Turning the resolution down, the smoke, dirt, dust, etc off, will improve the frame rate when those instances occur so if you are getting low fps when people in front blow up or get off track and kick up the dirt, turn those off. Use "Alt+F" to find out what your frame rate is and adjust or add the details and effects until you notice that the fps is below 36 to find the best resolution and level of detail for your system. Test with a few AI cars on the track to make sure it will still keep the fps up if you get into some traffic. Setting the detail slider lower is a good start if you are getting low fps. Turning down the number of sounds heard can also help improve the frame rate in some cases.