Motherboard wont detect 3-pin fans and they just run full speed

Tauno M

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Sep 14, 2013
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Hello!

I have 2 140mm 3pin fans on my PC case but i cant seem to make them work like they supposed to. On old Gigabyte motherboard i had these same fans for some time and it regulated fan speeds perfectly.

Now i bought (actually, a year back) new motherboard and other components. Case and fans i reused. Im not sure what i do wrong with my new board but it is not slowing down 2 system fans at all. They seem to be at full speed or somewhere close to it - at least it is how it sounds, very loud. I have them unplugged since i couldnt stand the noise.

Actually, third fan, the one that came with case, runs about 50% constantly and it is quiet enough and i can regulate it in bios and with MSI Control center - this one is 3 pin fan and it sits in 4 pin Sysfan_1 slot on motherboard.

Other 2 (front and side) are 3 pin fans and sit in 3 pin slots (Sysfan_2 and Sysfan_3) but are running full speed and as i found out, they are not even being detected by bios, Aida64 or Speedfan. Im lost, how can i make my system cool but quiet.

My motherboard is MSI H87-G41 PC Mate
https://www.msi.com/Motherboard/H87-G41-PC-Mate.html#hero-overview

The motherboard manual says: pins support Smart Fan Control with linear mode... whatever it means.

Is it possible that my new board lacks the feature to get any info or control through 3 pin fan slots? My last one was about the same price range.

I read that one of my solutions may be to buy fan splitter and make all my fans run through Sysfan_1 that i can manually put to 50% (weirdly not allowing me to go lower than that) but it would be great if i could get them to work like they use to - bios would auto-tune speeds as needed.

Help guys, im lost...
 

Tauno M

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Sep 14, 2013
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18,510


Thanks but im not using molex connectors, only 3-pin ones.
 
look at the new fan and old fans. if there an extra wire (red and black are power). then other wire is telling the mb there a fan there. for a little more mney then a y cable pick up 4 pin case fans if you want the mb to ramp the fans. non ramping fans use voltage most will have 50 or 100 percent default. if the fan cant run at the lower 7v.
 

Tauno M

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Sep 14, 2013
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I am using same fans from my old system, i never removed them from the case. Those system fans have black, yellow and red wires.

So the system fans cant be lowered below 50% of speed if they do not have 4th wire?