What is static pressure important for?

Static pressure is important for cooling performance in situations where completely unrestricted airflow is not possible. This may involve, for example, a fine-mesh case intake or radiators and heatsinks with their closely spaced cooling fins. To ensure high airflow through these obstructions, as high a static pressure as possible is required.

Without sufficiently high static pressure, the desired airflow cannot be achieved, resulting in a loss of cooling performance.