John Gruber of Daring Fireball, reviewing the iPad 2, had a developer friend write a quick testing suite for the tablet's upgraded graphics:
For example, on my original iPad, with 200 on-screen sprites, the framerate dropped to 45 fps. On the iPad 2, with 400 on-screen sprites, the framerate remained at 65 fps. On the iPad 1, Guy's demo app dropped below 60 fps with about 100 animated sprites; on the iPad 2, it didn't drop below 60 fps until there were over 750 animated sprites.
After I showed him the results, Guy told me, "The results show that the iPad 2 is easily about twice as powerful as the original and that this speed gain is a freebie - you don't need to change your code structure in order to see significant gains.