A method performed by a physical computing system, the method includes disabling a display refresh process of a video controller of the physical computing system if no active display device is connected to the physical computing system. A physical computing system includes a video controller comprising a rendering engine and a display refresh controller; a memory controller connected to a memory; and a display controller to determine whether an active display device is connected to the physical computing system; in which a display refresh process performed by the display refresh controller is disabled when no active display device is connected to the physical computing system.