My recent tests proved that on Windows 10 (whether 1080p or 4K) Dorico runs more fluent using NVidia Geforce GTX 1060 (3GB VRAM) comparing to the crossfired D300 cards on my Mac Pro (Bootcamp Windows 10). My gaming machine has only 8GB RAM (while Mac Pro has 32GB). Both computers are hexacore (i5-8500 and Xeon E5) and have similar benchmarks. Comparatively, Dorico on my Mac Pro using bootcamp becomes sluggish in displaying high-density orchestral scores through even 1080p screen resolution.
Looks like the minimum system requirements for Dorico on Windows (if 4k monitor is used) may need to change to GTX 1060 or AMD Radeon RX 580 (both have not less than 3GB VRAM). (Recommending any graphic card with better 2d rendering performance and 4GB VRAM or above.)
P.S.: Dorico on my Mac Pro runs fine if the OS is macOS Catalina. (I don’t know how Dorico 3.x behaves with Mojave).