correct does not say.
All board, al least asus, each PWM fan ports, unless is especified, uses 1 amp MAX per port.
On each fan on the back is amp rate. make a sum and do not pass 1AMP per port.
you board ahs 3. one is for the cpu. CHA_FAN1 and CHA_FAN2
you can put one on the back of case on 1 and a splitter on Cha2 to the 3 fans. So you need a PWM splitter (cost like 4usd) Just make sure does not pass 1amp the sum of the fans
I've never been concerned about running 3 fans from one header. If you are worried you could always use a hub that has separate molex power and only uses the motherboard for control.
First, thanks all expert's reply. Yes, I also suggest one fan for one header to avoid some fan issue. Thank you.