Just got a Dell XPS 8910. The integrated graphics card is an Intel HD Graphics 530. The discrete graphics card is an AMD Radeon RX 480 with 8gb of memory.
When I connect a monitor using the HDMI connector for the integrated card, all works well. When I switch the cable to the HDMI connector for the Radeon, the screen displays a mishmash of broken colors with content being barely discernible. The system tray has a "Radeon Settings" icon, but clicking on it while connected to the integrated card shows an error dialog box indicating that I need to connect to a Radeon card first. But I can't see the screen well enough when the Radeon card is connected to tell what I'm clicking on.
Any assistance will be greatly appreciated.