In my project i found, From App Icon click to Splash Screen is taking time upto 3 seconds. (Before going to didFinishLaunchingWithOptions).So i create an empty project without single piece of code written from my side. Then i tested the same problem with empty project still the issue remains. I have run the project using developer/enterprise Profile and XCode 7.3.1.
The Other Applications downloaded from App store, this issue is not found. They are launching within 1 second.