Certain apps, such as streaming music apps want a lot of contiguous memory. Some mapping apps have the same need. Without this, they run poorly or not at all. In fact, if the memory is fragmented, the entire phone may run poorly (slow typing, slow app loading, freezing or locking up, etc.).
It's related to both the app in question, and whatever apps you were running recently. If the previous apps don't clean up after themselves well, or if you were running a bunch of apps (opening and closing them), the memory in the phone might be fragmented.
The easiest way to deal with this is to periodically turn the iPhone off - really off, and then back on again.
An iPhone is just a small computer. When we do the typical 'turn it off' (i.e. hold the sleep/wake and home button, and then slide to turn off), we're really not turning it off. It's closer to a suspend, hibernate or sleep state.
To really turn it off, do the 'turn off' procedure, but rather than sliding to turn off, keep holding both buttons for a few seconds. The screen will flash and then the phone will turn off. Pressing the sleep/wake button (notice how Apple calls it a
sleep/wake button, not an
on/off button?) will then turn it back on. Just like on a big computer, give it a few seconds to snooze between the off and on process.
You'll see the white apple as the phone starts up. Once the apple is gone, your iPhone is ready for use.
Apple refers to this as "restarting" the phone.
It's much faster than the pain of restoring (you don't need a computer with iTunes nearby), and unlike 'turning off/hibernating/sleeping', it actually clears and 'defrags' the memory.
Note: Someone might chime in that they never have this problem, and you shouldn't have to do that and it's the fault of the App, and whatever. That might be true, but I'm dealing with your issue here, not their non-issue. Resetting the phone is what Apple will tell you to do in this situation, so go for it.
http://www.apple.com/support/iphone/assistant/phone/#section_2
coop
