Calls and contacts
Apps and media
Cause 1 of 2: There are too many running applications
If you've used many applications on the phone, it may get slow because the applications keep running in the background.
Solution: End running applications.
End running applications
Press the Application key.
Slide your finger downwards on the screen.
To end one running application, slide your finger right on the required application.
To end all running applications, press CLEAR ALL.