This game has done terribly to optimise textures, but is alright (just) with processing power.
You have a nice processor but your G-card could improve, so i recommend reducing view distance and texture + object settings. If your ceating your own mission, add some fog to it (at least for testing) - it greatly increases the fps :)
I have the same processor as you, and it's water-cooled. I really want to OC it but every tutorial I've read about OCing is quite complicated, and I definitely don't want to damage my processor because of a silly mistake I made. Since you have the same processor, could you breifly explain how you did it? I don't need a 3 page essay, i should be able to make sense of it xP - Don't feel you have to though :)