fans not always spinning

[Tupro]

So i recently got a new case + new fans
all fans are phanteks PH-F140SP (http://www.phanteks.com/PH-F140SP.html)
Input Current
0.14 A
Rate Voltage
DC 12V
Input Power
1.8 W

motherboard is gigabyte GA-Z87X-UD3H
I have 5 case fans and 4 are running off of splitters (2 fans per splitter)

The trouble im having is occasionally on boot up some or all of the case fans do not spin up until i either load up the gigabyte fan control software (system information viewer) or change the fan curve i have them set on (minimum 40%)

These are all 3 pin fans however my motherboard allow me to control the RPM via bios or software - i have it done via bios at the minute but sometimes have to load up the software once in OS to start the fans spinning
My motherboard bios has 4 options for controlling the fans
Normal - Silent - Full speed - Manual

right now i have them set on manual which gives PWM options from .75 to 2.5 (i have it on 1.25 which has them spinning around 650-700 RPM)

at first i thought it was maybe too much power drawn from 1 header but each fan is only 0.14A so running 2 off the splitter would still only be 0.28A so surely that couldnt be the causing it

only thing i can think of now is maybe im not giving them enough power by lowering them to 40%

any ideas??

 

[Tupro]

May have sorted this.
Think i was right and by lowering the speed to 40% via the motherboard (which lowers voltage) they weren't getting enough power to ensure they started up

got rid of the splitters and put 3 of the fans onto theyre own headers + put the other 2 onto a fan controller... seems to be doing the trick and only a little bit louder