If ya have a Sony 900e, please try this. Also, any other 4K set should work similar to this just different steps.
Set the Dish Hopper3 "Video Resolution" at "720P" or "4K, 1080p, 1080i"...Now go to any "Single" Channel, then with the Sony TV Remote, Press the "DISPLAY" Button. When I do this it shows: 1080i HD 16:9 0r 720P 16:9 (Depending on the Hopper3 Video Resolution)...
Now with the Dish Remote select "PIP" then select "MultiView" (4-Screens) Again use the Sony TV Remote, Press the "DISPLAY" Button. When I do this it shows: 3840 X 2160p 4K 16:9.
The "Multiview" pictures are drop dead gorgeous. The "Single" screen sucks on my set. I know a smaller screen will be harder to see artifacts but that's not what's going on.
I tested this in "Side By Side" (same size screens displayed as MultiView 37" each) When I Press the "DISPLAY" Button in "Side By Side" on the Sony TV it shows: 1080i HD 16:9 0r 720P 16:9 the same as the "Single" screen Resolution.
What results do you get?