chassi fan

I have these 4x12cm fans, 3 on front-intake, 1 exhaust. All of them are molex connector which directly comes from PSU and I assume they will run on max curve all the time, right? So, my concern is should I use these fans or look for another fans that is PWM connector from the motherboard...

Hey everyone, PC components: Cpu: i7-8700k Gpu:asus geforce rtx 2070 super dual evo ad motherboard: Mobo z370 i strix I bought a used pc when i tried to raise and lower the fan speed (beacuse is was to loud) . With applications like SpeedFan and Argus Monitor. I could only raise one fan not...