I can confirm that it is indeed quantitatively slower. The reason is due to the higher resolution; you have to render and scale pictures, which simply didn't t

I can confirm that it is indeed quantitatively slower. The reason is due to the higher resolution; you have to render and scale pictures, which simply didn't take as long on the 1440x900 of the air. He isn't wrong, you are just looking at different sets of measurables.