Some consumers may have found that having a 4K display does not always result in pin-sharp content. This is because 1080p image data is not always scaled effectively to match the more up-to-date resolution. NVIDIA has addressed this by introducing integer scaling in its latest Game Ready Drivers update.
https://www.notebookcheck.net/NVIDIA-addresses-an-issue-for-older-games-on-newer-displays-with-a-driver-update.433418.0.html