The new Silent Pro 14 case fans from Gelid did impress us positively because they are able to drive plenty of airflow while staying silent enough. The PWM feature means that it is not mandatory to have them connected to a fan controller in order to regulate the speed, but the fan RPM will be modified continuously based on the load of the system, when plugged in to the motherboard; PWM profiles can be also altered via the system BIOS in order to have a perfect balance between noise and cooling performance.