The Apple iPhone 4S might be a small upgrade if you were using the iPhone 4, but it is a huge upgrade if you are upgrading from the iPhone 3GS, as I was. Not only was the screen much sharper (albeit still the same size!), the iPhone 4S was much faster. Unfortunately, I also immediately noticed a big problem with the iPhone 4S - its terrible battery life. Recently, my brother pointed me to a very nice app called System Monitor with Battery Max. It`s a 99 cent app that allows you to monitor the hardware and software of your iDevice. What`s really nifty about it was it was able to give me a live read of the iPhone 4S` CPU load. What we found shocked us - the Apple iPhone 4S had a constantly high CPU load even when it idles!"
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips