I have a 3 pin fan header on my mobo and a 4 pin fan connector and this works fine, you can adjust speed in bios trough voltage. But there is one issue. The indication plastic on the 3 pon header is gone so i dont know which way to put it. And since my fan has 4 pins theres alot of different options.
https://ibb.co/xgZ1KFv
https://ibb.co/xgZ1KFv