Sadly, I can't run at that resolution. My monitor only supports up to 1280x1024. I am running everything maxed out, updated tire and track textures, and 4xAA 16xAF. LFS is mostly dependant on your processor (I have an AMD x2 4600+ at 2.4Ghz and 1GB RAM). With these settings offline I get between 110-140 fps but I usually cap it at 60 so I don't push the card too much offline or online and I usually have the LCD at a refresh rate of 60hz anyway.
It's a great card and I think it will match your rig perfectly. Is your proccessor overclocked?