Gaming CPU Fan speed, running too fast

[Zetta_x]

About a year or 2 ago, I had an HP desktop with a propitiatory foxconn motherboard. I ended up replacing it with an ASUS motherboard that had a 4 pin cpu fan slot. However, the cpu fan from the last computer only had room for 3 pins; it still plugged in. However, the second the computer starts up, it's loud as fuck. It's consistent, it's not changing the fan speed based on temperatures indicating it's not a heat issue (at about 32 C temperature it should not be running this fast anyways).

I think it has something to do with mixing the 3 pin fan with the 4 pin motherboard clip; it seemed like there was no other way to plug it in, so would I have to invest in a new cpu fan to fix this or was I able to shift it down a pin to fix this?

 

[Originality]

IIRC, normally the third pin is for reading the fan speed and voltage control. I never did find out what the fourth pin is for. If it's not reading the speed properly or if BIOS has been set with an over-protective CPU fan profile, then that can cause it to run at full speed all the time.

In my head, when I hear "loud CPU fan", I always read it as "time to get a new CPU fan". Arctic Freezer are great in that respect.

 

[Lanlan]

I always thought the fourth pin was a fan speed controller. But I could be wrong.

 

[Originality]

If you need 4 pins for all speed-controlled fans, how would the motherboard (or fan controllers) control the speed of the case fans, which usually come with 3-pin connectors.

 

[Zetta_x]

^^ That and the fan worked dynamically in the HP motherboard (only has 3 pins). I have been wanting to upgrade my cpu fan for a while; nothing fancy as within the next few years I'll probably give this to my brother and build another computer.

 

[chains_of_androm]

Get speedtemp, you should be able to manipulate fan speed that way.

 

[Armadillo]

4th pin is the pwm control signal.

4pins= fan speed is controlled by pwm. 3pins=fan speed is controlled by voltage.

Some boards have bios options to tell it whether you are using a 3pin fan on the header and to use voltage control on it or whether it's a 4pin fan and to use pwm control, some even auto detect. I don't believe Asus bios has the option. My 990fx sabertooth which is one of their higher end boards does not have it. Stick a 3pin fan on the 4 pin cpu header and you get no control.