[fritsch]

Could you please play it again a bit longer with 3840x2160 with debug loggin enabled? Then after 2 minutes press some button on the keyboard and enable the OSD? We want to understand what happens, e.g. what is stuck / too slow.  

 I used advancedsettings to enable debug without the overlay. If I switch on debug logging in the GUI it adds an overlay which mitigates it. 

Here you go: http://ix.io/1llE

I would be interested to learn why the overlay makes a difference. I see similar behaviour with netflix and amazon addons regardless of setting 1920/1080 resolution in GUI. 

@fritsch did this help? Need anything else? 

 I did not have the time to look. Busy private life at the moment. Will try over the weekend but cannot promise anything. Thanks for the information!