First, updating the video drivers may help.

Second, make sure hardware acceleration is enabled in Options > View > OpenGL page.

If you are still missing expected features like cast shadows or reflections in the viewport display, here are some things to check.

• Cast shadows: Are shadows enabled in the display mode for this viewport? Check the Display panel (Panels menu > Display) and make sure the Shadows box is checked.

• Reflections: Rhino can show environment reflections in the viewport if object materials have some reflectivity set. Reflections may not look like much if the environment is a flat color or a simple gradient. Setting a more active environment in the Environment panel (Panels menu > Environment) will give these surfaces something more to reflect.