The term refers to the maximum number of 120mm fans that a computer case can accommodate. This specification is crucial for determining the cooling potential of a system, influencing airflow and overall thermal management. For instance, a case advertised with this specification may house three fans at the front, three at the top, one at the rear, and two or three at the bottom, depending on design, plus one or two on the side panel and one or two internal to the hard drive bays.
A higher number of compatible fans allows for enhanced heat dissipation, enabling quieter operation at lower temperatures and improved performance of heat-sensitive components such as the CPU and GPU. Historically, chassis designs were less focused on airflow, leading to thermal throttling and instability. The evolution towards supporting a significant number of cooling fans reflects a growing awareness of the link between system performance and effective thermal management.