SUPERMICRO has tested several configurations for cooling the Pentium II Xeon CPU. The easiest and most efficient method combines this Xeon Cooling Kit with the SC750-A chassis and either the Xeon passive heat sink or an Intel retail package Xeon heat sink. The SC750-A comes with one 9-cm, 3-pin fan with hanger. This 9-cm thermal control fan is for back-up cooling and should be mounted along side the main fan (provided in the Xeon Cooling Kit). Also standard with the SC750-A is one 9-cm, 4-pin exhaustion fan.