Keep your expectations reasonable... I doubt you'll get 80 fps with the sliders all the way up and at high resolution. I personally prefer to turn the sliders down to half, run at 1280x1024 to match my LCD monitor resolution, and then add as much FSAA as I can until the framerates drop too much. Just keep fiddling with the settings until you're happy with what you see, and consider trading slider detail and view range for FSAA.