Is there a way to control a case fan's RPM when it is a 4-pin connected to a 3-pin header?

[pygmypiggy]

Hello, I recently bought two new case fans, these are the pair: http://www.newegg.com/Product/Product.aspx?Item=N82E16835181040

I have both of these fans connected to this Motherboard: http://www.newegg.com/Product/Product.aspx?Item=N82E16813128514&cm_re=gigabyte_990fxa-ud3-_-13-128-514-_-Product

So, the motherboard has two system fan headers, and one of them is only a 3-pin header.
After installing both of the fans, there is one fan running at full speed, at about 2000 RPM.
I was wondering if there was a way to calm the speeds down, or if i would be able to change them in BIOS, or Speedfan before I simply take it out. Thanks in advance!

 

[King Kevain]

Yes - but you'll need something like Fan Expert to do it or as you said, in BIOS, but will depend on the BIOS you are using as to how much and what you can do, alternately, you can use a manual Fan Controller - these range from very simple to very fancy - google "PC Fan Controller" and look under images and you'll get the gist.

 

[hwc1954]

You can have automatic speed control of PWM fans on the 4-pin CPU header. You can have voltage speed control of 3-pin or 4-pin fans on the 4-pin SYS fan header.

I assume you have PWM controlled CPU cooler fan(s) already connected to your CPU_fan header. You connected one of your new Corsair fans to the 4-pin SYS header and one of the new Corsair fans to the 3-pin SYS fan header:

a) The Corsair connected to the 4-pin header is being speed controlled, but as if it were a 3-pin fan, not using it as a PWM fan.

b) The Corsair connected to the 3-pin header is not being speed controlled, because the motherboard does not have speed control for those headers.

I see two good options:

OPTION 1: just move the second Corsair to the same SYS fan header as the first Corsair using a simple fan splitter:

www.amazon.com/PWM-Y-Splitter-Cable-Adapter/dp/B002OFP6QW

This will control the speed of both fans in unison. The two fans have a combined current draw of 0.36 amps so there is no problem hooking two of them to a single header. The only disadvantage is that you are not using them as PWM fans.

OPTION 2: Hook both of your CORSAIR PWM fans to the same CPU header as your PWM CPU cooler fan. To do that without overloading the fan header, you need this splitter.

http://www.amazon.com/gp/product/B00DYQRFY6

It connects to the PWM signal pin and the TACH SPEED SENSOR pin of the fan header, but gets the +12V and GROUND signals from a PSU molex. This lets you safely control four PWM fans from a single CPU fan header. This is probably what I would do with your system. NOTE: this option only works if you have PWM fans on your CPU cooler. If you don't, then use OPTION #1.

Also, if your MB software allows you to set different fan control curves for the CPU and CHASSIS fan headers, then you would want to use OPTION #1 if you care about controlling the case fans and the CPU fans differently. I don't know if your MB has this option. Usually all of them are controlled based on CPU socket temp which is as good as another other way.

 

[pygmypiggy]

Thank you both very much for your answers. I went back on, and I could only find an option to control the RPM of the stable fan, but not the one at 100% speed. I also could not calm the speeds down in Speedfan. I think the best thing I can do is what hwc1954 suggested, and get a splitter. I have another question about this splitter though. You said that it only works if i have a PWM fan on my CPU cooler, so just to be completely safe, do you know if it is compatible with this heatsink/fan? http://www.newegg.com/Product/Product.aspx?Item=N82E16835103100

Sorry if I sound like a total moron, I've just been having a little bad luck with incompatibilities lately, haha.

EDIT: Nevermind, I actually bothered to look at the specifications, it should work.

 

[hwc1954]

Yes. Your CPU cooler has a PWM fan. You would be all set to hook up all three fans (CPU and 2 Corsair PWM fans) to the CPU header as I described in OPTION 2.

Since you use SpeedFan, the only disadvantage would be that you will only see the speed of one fan (either the CPU fan or one of the Corsairs). They will all be controlled in unison, but you will only see one fan speed in Speedfan.

If you use OPTION 1 above (connecting both Corsair fans to the 4-pin SYS FAN header with a simple splitter), you should see separate fan speeds in SpeedFan for the CPU fan and for the Corsair chassis fans. If you care.... Same thing if you would like to control the fans separately in SpeedFan. Option 1 would let you separately control the speeds of the CPU fan and the two Corsair fans (as a pair). Option 2 means that you control all three fans as one group.

I kind of like seeing separate fan speeds reported in SpeedFan, so when I think about it, I would probably go with OPTION 1 for that reason. Doesn't make any difference from a cooling standpoint, just makes for better SpeedFan viewing!

 

[pygmypiggy]

Awesome! I'll go with option one then, and pick that splitter up soon. Thank you again for the answer, have a good one!