One of the feature everyone liked about the Internet Explorer 9 beta was the Add-On performance Advisor which checks if any installed add-ons are slowing down your browser’s startup time. It will notify you once it opens if any add-on is slowing down and you can set the threshold for the total add-on time to load. This is an excellent feature as some people may blame IE while the actual fault might be the slow add-on. So performance is one of the features, Microsoft is really working on.
In the same manner, Microsoft has set some Windows Phone 7 Application certification requirements. So your App has to pass these requirements if it has to be certified.
If you have developed an App for Windows phone 7, on the performance front, it will not pass the certification unless these requirements are fulfilled-
The application must render the first screen within 5 seconds after launch.
Microsoft recommends that the application provides a splash screen image only when it takes longer than 1 second to load the first screen.
Within 20 seconds after launch, the application must be responsive to user input.
If you have seen any demo of Windows Phone 7, you must of noted the OS being smooth and responsive even when these are not the final ver for software and Hardware. So to keep this smoothness, Microsoft has set the requirements for the Apps developed for it.
Check out more about performance requirements and other Windows Phone 7 App requirements required for it to be certified.
Download it from - http://go.microsoft.com/?linkid=9730558 (PDF ~522KB)