Connecting 4-3 pin headers

[iSprinKle]

Hello,
I'm getting the Z77 Sabertooth, which has 4-pin fan headers, but the Thor case I have has fans with 3-Pin heads. Will they still work?

 

[manofchalk]

Yes.
That last pin is the PWM signal, which tells the mobo how fast the fan is spinning. The mobo can roughly guess the RPM of the fan by the voltage its providing, just the PWM is more exact.