Why can i control 3-pin fans like PWM fans?

[Chickenator]

Yesterday i discorvered that i can use 3-pin fans on my MB (asus maximus vi hero) and control them like they were 4-pin PWM fans.

Used AI Suite's Fan Xpert 2 to do so.

I thought they could only be regulated by voltage. Why can do they act like PWM fans?

 

[Brantyn Gerik]

it's just how fans work, some motherboards can vary the voltages given to the fan connectors, and thus, even if you were running a 4 pin fan with a 2 pin connector, as long as the functionality is there, you could still control it just like you would using a 4pin connector (i use this example because this is what i have done and it works perfectly fine at all speeds)