CPU Benchmark is a speed testing tool to let you visually see how much you are gaining moving your Droid from 550mhz. It shows you a bar graph comparing your different speeds. I recommend running the test a few times at each speed to get a good average.
This can also be a way to compare two Droids of the same speed to see if your background tasks are eating up a lot of CPU time or to compare to your friends G1 to make them jealous.
The app is up on the Market or you can download the APK file directly at:
Unstable Apps - Mobile apps for a mobile world