We do still highly recommend running the GUI at 1080 and allowing refresh rate switching which also allows for resolution switching above the GUI resolution as well. It is expected for the upscaler in your TV to produce better quality than the Vero so even if there wasn’t a performance hit in the GUI by running that in 4k it would still not be ideal for all your content to be output this way.
Correct
I’m sure you have seen this quite a few times now but just for posterity’s sake…
We recommend people with 4K TV’s set their user interface (UI) to 1080p. Kodi’s UI is not optimized for 4K yet and this can put unnecessary demands on your device and can lead to a suboptimal picture quality, as well as potentially cause other issues.
The settings we recommend are as follows…
Settings>System>Display>Resolution> 1920x1080p
Settings>System>Display>Whitelist> (empty) *
Settings>Player>Videos>Adjust display refresh rate> On start/stop
Some televisions may also need, or benefit from, the following being set…
System>Display>Force 4:2:2 colour subsampling> (enable)
With the above settings your UI will be output in Full HD and your 4K content will be output in 4K. *Information regarding the whitelist can be found here. If you have any doubt, feel free to upload some logs so we can verify that your settings are indeed correct.