1. Turn off your Galaxy S6.
2. Press and hold Power, Volume Up and the Home button.
3. You'll see a blue screen with the Android on it, then you'll be taken to the recovery menu.
4. Use the volume buttons to scroll and highlight Wipe Cache Partition. Press Power to confirm.
5. You'll see a message in yellow at the bottom of the screen when the process is complete.
6. Highlight Reboot System Now and press Power to confirm.
7. Your Galaxy S6 will reboot and recompile all of your apps. It might take a little while to re-cache them all, but once it is done you should have a Galaxy S6 running as smooth as can be.
If your clear cache of s6 but still unable to solve the problem, you should open up the phone, disconnect the flex cables of battery and display screen and reconnect them after a while. Because of overheating, the connectors of battery and display screen may get loose or burned. And it is also possible that your display screen is broken, you should get[ https://www.witrigs.com/oem-lcd-with-digitizer-for-samsung-galaxy-s6-blue| a new screen for your Galaxy S6].