CPU cooling fans play a crucial role in maintaining the proper temperature of a computer's central processing unit. They are designed to dissipate the heat generated by the CPU during operation. The basic principle of a CPU cooling fan is to create airflow over the heatsink attached to the CPU. The heatsink is made of a material with good thermal conductivity, such as aluminum or copper. It absorbs the heat from the CPU and the fan then blows air across the fins of the heatsink, carrying the heat away.

There are different types of CPU cooling fans. The most common ones are axial fans. Axial fans have blades that rotate around an axis and draw air in parallel to the axis of rotation. They are relatively simple and cost-effective. Another type is the centrifugal fan. Centrifugal fans work by drawing air in at the center and expelling it radially. They are often more powerful and can generate higher pressure, which is useful in some compact computer cases where the airflow needs to be forced through a more restricted space. The size of the CPU cooling fan also varies. Larger fans can move more air with less noise, but they may not fit in all computer cases. Smaller fans are more compact but may need to spin at a higher speed to achieve the same cooling effect, which can result in more noise. The fan's speed is usually measured in revolutions per minute (RPM). Higher RPM means more airflow but also more noise. Some advanced CPU cooling fans come with features like PWM (pulse width modulation) control. This allows the motherboard to adjust the fan speed based on the CPU temperature, optimizing cooling efficiency and noise levels.