Apple already told us when they unveiled the iPhone 4S that it is much faster than the iPhone 4. Now we know already how much faster. Some iPhone 4S benchmark reports appeared already on GLBenchmark. Anandtech has a good presentation of the report and some conclusions.
Interesting is also that the A5 CPU in the iPhone 4S is running on a lower clock speed than on the iPad 2. Apple is doing this to conserve battery life. The iPhone 4S is likely clocked at 800Mhz.
The GPU is also slower than on the iPad 2, but still way faster than the Galaxy S2 or Galaxy Tab 10.1.
More iPhone 4S News.