Ok, I looked at your motherboards manual and I can understand your confusion. The Connectors labeled PWR_FAN1 and PWR_FAN2 are intended to be connected to a fan inside or attached to a power supply. The ones labeled CHA_FAN1, CHA_FAN2 are intended to be used with chassis fans at the top, front, bottom and/or back of your case. Since most power supplies come with sufficient fans built in, you don't need to connect these fans to a power supply, however you can use them as additional chassis fan connectors. BTW, I also noticed that the CHA_FAN1 is a four pin connector so you can use a PWM fan on that connector if you want to.