Sorry, you can't do that. Your mobo has 5 fan headers in total - see manual p. 21-22. The two CPU_FAN headers are only for use with a CPU cooler. You use ONE of these, depending on whether your CPU cooler is a 3-pin or a 4-pin fan. There is a 3-pin header called PWR_FAN1 whcih is not designed for use to control any case fan. Then there are two 4-pin headers called CHA_FAN1 and 2. The labels on their pins clearly indicate that these are true 4-pin fan headers operating only in PWM Mode, and the brief details on p. 80 do not indicate anything different. Now, you can NOT control any 3-pin fan with that type of fan header. A 3-pin fan connected there will always run at full speed no matter what you do. The ONLY fan type that you can control...