Why might a computer cooled by a constant-speed fan operate satisfactorily at sea level but overheat at high altitude?

A computer cooled by a constant-speed fan may operate satisfactorily at sea level due to the denser air, which allows for more effective heat dissipation. At high altitudes, the air pressure and density decrease, resulting in reduced airflow and cooling efficiency from the fan. Consequently, the cooling system may not be able to remove heat effectively, leading to overheating. Additionally, lower ambient temperatures at high altitudes can exacerbate thermal management issues if the fan speed remains constant.