Arctic uses a fan to cool another fan — S12038-4K 120mm fan adds an extra fan in its center to cool its central shaft
by from Latest from Tom's Hardware on (#6SS2F)
Arctic's new S12038-4K/8K server fans have an extra set of fan blades for the true cooling enjoyers. Really, the extra blades are to cool its own center shaft, which may be necessary based on the fan's class-leading performance.