Overall the 3DEXPERIENCE scales pretty well on a 4K screen. There are still things to improve here and there and it will be taken care of in future releases. In the meantime here a couple of best practices:

• Even if not mandatory (on Windows 10), you better log out from your Windows session after having changed the scaling % in the Windows settings (Display settings / Scale and ayout) to ensure the CATIA native client user interface scales well everywhere ;
• If you have 2 or mores screens, and work in extended desktop mode, define the screen CATIA is displayed on as the primary screen for the scaling to be taken into account ;
• To gain performances, anti-aliasing quality can be decreased if not turn off on smaller screens. This is done from the Visual Quality panel (command in the View section of the Action Bar)
  

In the CATIA Design Portfolio team we use 65" and 85" 4K touch screen from Planar, mostly to present design projects with CATIA Product Perception Experience.

Please drop a comment to let us know if and how you use 4K screens in your design activites!