At 1280 x 1024 with AA & AF off (application preference)100 fps (monitor refresh rate) 100% of the time. I haven't tried any higher refresh rate but when I tested it with v-sync off it ran in the 200+ range most of the time(only flew around breifly, no furballs, smoke or anything difficult to render)
My prefered set up is 1280 x 1024, AA x4, AF off, all sliders max quality, refresh rate 85Hz (better quality image than higher rates on Samsung 21" CRT). Runs at 85 FPS 100% of the time. With the card declocked to XT spec, the frame rate will breifly dip into the 70s in furballs with a lot of smoke and buildings present (as in base defense)