passive cooling
Passive cooling is an approach to cooling computer components through slowing the speed at which the component, such as the processor, is operating. That approach contrasts with active cooling, which involves using fans in preference to slowing the speed of the component.
Typically, a combined approach is used, in which either active or passive cooling is selected as the first option. In power management settings, for example, selecting passive cooling means that the system software will slow down the component to make it run cooler and only increase fan speed if necessary to keep the component at an appropriate operating temperature.