I run lfs at everything maxed out (even in nvidia control panel) and at open configs I get 20+ fps (well, when the start grid is full, I get ~10 or less).
My pc: AMD Athlon 64 3000+ 1,8 GHz (single core), 2gb RAM, 1 gb VRAM (actually, my win 7 professional shows it is 512 mb, but I know it is 1 gb and my previous windows, windows xp showed 1 gb).