In case you missed our inaugural coverage of the iPhone 4S, check back to Apple iPhone 4S, Part 1: More Horsepower, Better Hardware. In that piece, we ran preliminary input lag benchmarks and turned up an improvement as great as 50%.

Improved performance comes at a cost, unfortunately. This phone's battery dies approximately 7% to 8% sooner than the original iPhone 4. The good news is that you only take a hit when you performance CPU- and GPU-intensive tasks like decoding a video stream or playing a game. When you're just browsing the Web or listening to MP3s, battery life doesn't really change at all.

We're using the same tests here as you've already seen in our tablet reviews. For more information, read page 11 of Samsung Galaxy Tab 10.1: A Second-Gen Android Tablet.

Interestingly, recharge time doesn't change by any substantial margin. If anything, charging back up takes less time on the iPhone 4S. That's good news if you rarely sync your smartphone, and consequently have fewer opportunities to maintain a full charge.

Relatively-unchanged battery life is in sharp contrast to the wireless networking and gaming performance proffered by the iPhone 4S, both of which were covered in Part 1. This time around, we focus on Apple's improved camera hardware, the iPhone's display, and Siri.