…around 36 hours, actually…
Gizmodo has an article talking about the new phones and the speed. Here's an excerpt that made me laugh:
Like we said before, the iPhone 3G will still run most of the games for the near future. That 40 million unit potential market of iPhone/iPod Touch devices is too big to just ignore and put out an app just for 3GS phones, so your old phone will still be able to keep up. But developers are like alcoholics. If you put more system resources in front of them, they can't help but use all of it just because they can. Also, they drink a lot.
Read the whole article, and watch a video of side by side iPhone 3G and 3GS showing speed related issues over at Gizmoodo.
Gizmodo: iPhone 3GS Review
