I dont know if its true, but i'm sure i read somewhere that if you alt+tab out of LFS, then go back into it it doesnt have AA and AF any more, and people were saying they were getting more FPS, but only because the AA and AF werent being used. So maybe thats whats been happening before.
Just turn AA and AF on (as high as they will go) in your card settings (make sure its set to always on and not game specific) load up LFS, put it on the highest resolution, run a replay (then you can slow it down if you get bad FPS because of the increased resolution) and press print screen. Go into photoshop, paintshop pro or whatever and paste it ... its not that hard