Why iphone app start slowly?

i'm newbie in iphone dev, i got an issue with running an app in my iphone device. I added my provisioning profile to xcode and build successfully in my iphone (iphone 3G). But, i don't know why when the app start, it takes 2 seconds to run the app.my app is a sample project create 开发者_如何学Pythonby xcode (file - new project - view based application), i don't add any more code to it. i wonder that: does my provisioning profile make it slowly? Please help me ...

Are you sure that the other applications are actually starting faster than your test case? 1-2 seconds has been the minimum startup time for applications that I've tested on the older iPhones. For example, see James Thomson's description of the startup time optimization he performed on PCalc, where he measured that it takes ~1 second to even begin the startup process in your code.

Perhaps what you are seeing is the default image that most applications throw up on screen when they launch, making them look like they're starting faster. They aren't actually responsive until 1-4 seconds after the launch, but they have the appearance of a fast start.

Your app will start slow if you run it from the XCode debugger. The reason is that there is lot of communication between the app and the debugger.

To have a realistic measure of the startup time, install the app via XCode, but start it from the iPhone's home screen.

Check for:

1- Your iPhone available memory, and for the background processes. You may use Mobile Substrate profiling tool (Available via Cydia only).

2- Use Instruments to check your code runs on the device, and compare it to the simulator's results

Check your OS version, if it is 4.0 then you cannot do anything because it has been seen that some applications runs slowly on OS 4.0 in comparison to OS 3.x The reason for that is, iPhone 3G is not fully supported the OS 4.x. You have at least 3GS device for full support.