Connect the two Front Intake Fans
There is a better way to control the speed of the two Front Intake Fans.
Your Motherboard has two Chassis Fan Connectors along the right edge.
Locate the Chassis Fan 1 Connector marked CHA_FAN1
It is right next to the 24-Pin Motherboard Connector.
Connect the Front Fan 1 power cable to the CHA_FAN Header
Locate the Chassis Fan 2 Connector marked CHA_FAN2 on the bottom right.
Connect the Front Fan 2 power cable to the CHA_FAN2 Connector