PS... I ran across this thread at the SimHQ site that could help you out:
http://simhq.com/forum/ubbthreads.php/topics/2644659.html
Seems that other ATI users are having problems also with SF... I'm running EVGA 2x 7800GTX KO's and just had to lower my setting a bit as I only have a single FX-57 CPU.