Here's a fun video of four generations of the iPhone -- original, 3G, 3GS, and 4 -- performing the same tasks simultaneously. From launching intensive apps like Plants vs. Zombies and Google Earth to shutting down and booting up, the differences in task durations are often significant.
As you'd expect, the iPhone 4 out-performed its peers on most tasks. For example, it had Plants vs. Zombies ready to play in 8.5 seconds, while the original iPhone took 26 seconds to reach the same point. Likewise, the iPhone 4 had Google Earth ready to go in 21.4 seconds while the original took just over 37 seconds.
Now, don't think the iPhone 4 won every contest, because it didn't. The original iPhone was the first to complete the shutdown process at 8.2 seconds, while the 3GS was the first to successfully boot up at 26.4 seconds.
You can watch the video after the break.