4 Pin header without PWM

Hi,

I am planning to go with Asus ROG Hero VII which has:



2x CPU fan headers (4pin with PWM)

and 4x Case Fans (4 pins without PWM). Apparently motherboard controls the fans with voltage. I have few questions with regards to that:

1. What is the difference between PWM and 4 Pin Voltage Controlled Header?


2. If I would like to add extra fan to the motherboard is there any splitter for that? (I would like to have all fans controlled)


3. How does the motherboard control fans (I.e. does it adjust speed to temperatures in case? Does it have any sensors ??


4. For the voltage controlled fans do I need them to be PWM?

Thank you