Hi I'm about to build a system based on a Gigabyte GA-X99-UD5 m/b and I want to make sure I buy the right fans. All of the fan connectors on the M/B are 4-pin.
The manual seems to imply that ALL of the fans are PWM controlled, because for every fan they allow you to specify 75% PWM value per centigrade thru 250% PWM value per centigrade.
BUT the pinouts they give are different: The pinouts for the system fans are 1=GND, 2=speed ctl, 3=sense, 4=VCC. However the pinouts for the CPU fans are 1=GND, 2=+12V, 3=sense, 4=speed ctl.
I've never seen a 4-pin fan that isn't PWM controlled. So why the different pinouts?
