Outdated or incompatible graphics drivers may prevent AutoCAD from recognizing your GPU.
When you see "gdi16.hdi (Software)" in your settings, it means Hardware Acceleration is disabled . Instead of using DirectX to communicate with your GPU, AutoCAD is using your CPU to emulate graphics rendering via the Windows Graphics Device Interface (GDI). Why Is AutoCAD Using gdi16.hdi Instead of My GPU? autocad virtual device gdi16.hdi
The file is part of the HEIDI (HOOPS Enhanced Interface for Desktop Integration) graphics system used by Autodesk products. autocad virtual device gdi16.hdi
The most common cause is simply that the feature has been toggled off. autocad virtual device gdi16.hdi