Use a 2-pin ATX fan on a 3-pin mobo PWM controller?

moeburn

Honorable
Aug 6, 2013
14
0
10,510
I have a spare 120mm fan lying around, and I want to use it in my case, but it is too loud at full speed. I tried soldering a 150 ohm potentiometer to it, but the fan draws so much current, that the pot gets kinda warm. It's probably fine, but it's not the ideal way to do it. Plus, it would be neat to be able to control this fan using software.

The fan uses the v+ and ground from a standard 4-pin ATX power cable. Could I solder these to v+ and ground on a 3-pin motherboard fan connector cable? I know the 3rd pin is for sending RPM info back to the motherboard, and this fan does not have that capability. Is this required? Would the PWM still work, using SpeedFan of course (not the BIOS fan speed controller), even without the RPM wire?
 

moeburn

Honorable
Aug 6, 2013
14
0
10,510


I'm not sure I understand... So I guess the fact that those exist mean this WILL work? I recognize the little white cables coming out of the molex, but what are the black ones? And it says 12v/5v? I'm pretty sure this is a 12v fan, what voltage are the mobo connectors then?