Well, it looks like you weren't imagining things if you thought in-app browsers or web apps saved to your iPhone's home screen seemed slower than Safari itself. Ars Technica
, which the site found to be about 2.5 times faster than Safari in iOS 4.2. The problem is that those apps don't have the necessary permissions to execute dynamically generated native code stored in writeable memory (as Safari does), which basically leaves them running at the same speed they did in iOS 4.2. Not surprisingly, that has prompted some to speculate that it's all part of a grand plan on Apple's part to force developers to use full-fledged apps instead of mobile apps, but Ars Technica
points out that it could just as easily be due to some technical problems. Hit up the source link below for all the technical details.