the way i learnt to notice the difference is to play quake III at 800x600 and use the zoom button in any level and look at the jaggies on a wall edge or something, they are real obvious. now switch on AA (highest setting u can) and dont change the resolution. ull notice the gfx look better than before, but now zoom in again on the same level and look at the same wall edge - ull notice the jaggies are smoothed off (although still slightly visible). thats my lil test.