If the fans have only 2 wires going to them, the motherboard can't control the speed. (The 2 wires are +12V and Ground.) A 3 wire fan would allow you to monitor the speed but not control it*. A 4 wire fan would allow the board to control the speed by Pulse Width Modulation. But the board would have to have a 4 wire header.
*all 2-wire 12V fans w/universal DC motors can be controlled by varying the DC voltage to the motor, but that would take a separate controller.