Switching onboard/offboard active video (TS4-1686449 / TS4-187485002 / TS4-1910483)
Reach BIOS settings by repeatedly striking the 'del' key during system boot/splash screen.
Navigate to ‘Advanced’ → ‘PCIe/PCI/PnP Configuration’ → ‘VGA Priority’
Most GPU servers are setup to use offboard video display, which utilizes a display port from one of the installed graphics card that is pointed out in your system’s info flier.