Molex case fan is LOUD - How to make it quiet

[mcgge1360]

One of the 3 fans on my case uses molex instead of the 3/4 pin fan headers on the motherboard. The problem with this is that I can't change the speed of it, so it always runs at max speed. Having 4 fans in my case total I set all the fans to a silent mode and get quite good airflow. Except the molex fan is bugging me. I am a tinkerer to I don't mind messing with the wiring, and I have 10K, 1K, and 220 ohm resistors available. Someone wanna show me how to make this fan silent. I want it to ran at about 20-40% of it's current (100%).

If there are any other ways too I would love to hear them, preferably without buying a molex fan controller.

Thanks!

 

[Eximo]

Re-wire it for 7V:

Yellow, Blk, Blk, Red
12V, GND, GND, 5V

Swap the ground with the 5V line on the fan side. That will get 7V and the fan should spin around half speed.

If your PSU wires aren't colored, I suggest a cheap multimeter to check the voltages before hand.

 

[geofelt]

simplest is to use a zalman fanmate if your fan has a 3/4 pin input.
Otherwise a simple speed reduction cable will work:
https://www.maplin.co.uk/p/speed-limiting-cable-12v-to-7v-a98bc

What is your case and the fan layout?
If the offending fan is an exhaust fan, remove it entirely.
All cooling air that comes in the front will exit somewhere.

 

[mcgge1360]

Re-wire it for 7V:

Yellow, Blk, Blk, Red
12V, GND, GND, 5V

Swap the ground with the 5V line on the fan side. That will get 7V and the fan should spin around half speed.

If your PSU wires aren't colored, I suggest a cheap multimeter to check the voltages before hand.

Does it matter which gnd?

 

[Eximo]

Re-wire it for 7V:

Yellow, Blk, Blk, Red
12V, GND, GND, 5V

Swap the ground with the 5V line on the fan side. That will get 7V and the fan should spin around half speed.

If your PSU wires aren't colored, I suggest a cheap multimeter to check the voltages before hand.

Does it matter which gnd?

There should only be one ground to move... 12V+ and GND, going into a 4-pin connector. GND becomes 5V when you do this swap. 12V-5V = 7V.