Motherboard doesn't have PWM based fan speed control?, what should i do if i want to have auto fan speeds?

Nov 16, 2018
Been in the market for replacing my stock nzxt s340 fans for a while, they are connected via molex and are always 100% speed which gets quite loud.
I was on the noctua website and found this page

The little graphic titled "4 pin header types" really confused me and i looked up if my motherboard had pwm based control or voltage based control and it seems that it is voltage based?

The paragraph under the image noctua has states..

"However, if Pin 2 is described as “Speed Control”, you can also be sure that the fan header does not support PWM based speed control." Pin 2 is described as "speed control" in my motherboards manual.
Kind of lost as to how i can get automatic case fan speeds, is voltage based speed control the same as PWM speed control? can i still set up fan curves if my sys_fan header is voltage based? Any advice would be appreciated, i'm pretty new in terms of computer building.

Motherboard in question

Motherboards manual