be quiet! Dark Rock Pro 4 CPU Air Cooler Review The Dark Rock Pro 4 promises two things right up front, "NO COMPROMISE SILENCE AND PERFORMANCE." be quiet! even says it in all caps, so it must mean business. Other marketing speak is "Silent Wings," "Funnel-shaped," "high-performance," and "easily installable." We will put it all to the test on our highly over-volted Ryzen 7.