The NA-FD1 airflow set for Noctua coolers enables significant performance improvements in compact cases where there is a gap of at least 5 mm (up to 45 mm) between the fan and the perforated side panel or top of the case. By bridging this gap, the cooler draws in only fresh air from outside and no longer pulls in warm air from inside the case. This can lead to a reduction in CPU temperatures of up to 5 °C, depending on the system.