Why do all-in-one machines need to install many fans?

On the metal cover inside some all-in-one computers, a turbofan can be seen. Strangely, there is no heat pipe at the front of this fan, making it seem like a "useless" fan. In fact, as long as you observe carefully, you will find that at the front end of this fan is the motherboard chip heat sink, and the fan can take away the heat on the chip. However, this is not the primary purpose of this fan. In fact, in order to form a reasonable air duct and reduce interference and electromagnetic radiation, a modular design is adopted. The motherboard is covered with a metal shielding cover, although the heat of its main heating components CPU and graphics card is transferred to the outer end of the metal shielding cover through heat pipes and discharged outside the machine by a fan. However, the heat generated by the chipset and the high position of the graphics card heat pipe itself will still cause the temperature inside the shielding case to rise, thereby affecting the stability of the entire machine. Therefore, adding this fan to the shielding case is precisely to allow the air inside the shielding case to flow, so as to dissipate the heat generated by the motherboard outside the machine. The all-in-one machine body is smaller than traditional computer cases, but it needs to accommodate components with higher power consumption than laptops. Therefore, the seemingly "useless" fan is actually designed to enhance the function of the air duct, which is the essence of the overall machine design.