Your best off really creating your own config file. Set the in game stuff to what runs fairly well, and then remove 32 bit colour and all the high detail mirror stuff etc, view distance etc and all the other bits and bobs which sound like prosessor hogs.
If you look at the entries in the file, they are in categories. One of them is mirror view. If you turn most things off in the mirror (come on, admit it, you only need to see the cars, tracks and walls) it'll probably run a lot quicker.