These are not PWM fans! So in PWM mode, the fans would spin permanently. However, some mainboards support PWM and DC mode with their 4-pin connectors. In this case, the fans can be controlled via the voltage. Just check the bios. It can also happen that only 3-pin connections of the mainboard are controllable. It would also be sufficient for case fans, as you can connect up to a maximum of 5 fans to one connection via an adapter.