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2 system fans plugged into MB but 2nd fan still runs at full RPM AND values of PWM/ degree C

I have a Gigabyte Mobo and (it being an m-atx) only has 2 system fan headers. So I plugged in 2 of my exhaust fans there. Both my exhaust fans are corsair af 120 LED fans. I booted in to my BIOS and set the system fan settings (both fans to be set at manual at 1.00 PWM/ Degree C) and rebooted and saved the settings. I went again into my BIOS and it displayed that while my 1st system fan was complying with the settings I set (running at about 600 rpm I think) the 2nd sys fan was running full RPM at 1600 RPM.

I really couldn't understand and find a fix how a fan plugged into the mobo still runs at full RPM. Is it because there's not enough power being delivered to the mobo etc? Please help me out.

ALSO! If you could answer this, it'd be great. What're the values of the PWM per degree C when you set the fan settings to manual? Like what is slope pwm and how fast is .75 pwm/ C 1.00 PWM/C etc. etc.

AND! By setting it to manual, does this mean the fans will ramp up when needed or not?

I'm so sorry for the plenty of questions, would appreciate and be suuuper grateful if you answered all of them. Thanks so much! :D
4 answers Last reply Best Answer
More about system fans plugged 2nd fan runs full rpm values pwm degree
  1. If these are your fans: http://www.newegg.com/Product/Product.aspx?Item=N82E16835181044
    ...they are not PWM fans. I don't know which MB you have, but it sounds like you may have one of the fans plugged into a 4 pin header. Is this correct?
  2. clutchc said:
    If these are your fans: http://www.newegg.com/Product/Product.aspx?Item=N82E16835181044
    ...they are not PWM fans. I don't know which MB you have, but it sounds like you may have one of the fans plugged into a 4 pin header. Is this correct?


    Yup. Both of my pans are 3 pins and both of them are plugged into 4 pin fan headers.... But one fan runs full rpm the other complies with the mobo's orders.
  3. Trez_YTR said:
    clutchc said:
    If these are your fans: http://www.newegg.com/Product/Product.aspx?Item=N82E16835181044
    ...they are not PWM fans. I don't know which MB you have, but it sounds like you may have one of the fans plugged into a 4 pin header. Is this correct?


    Yup. Both of my pans are 3 pins and both of them are plugged into 4 pin fan headers.... But one fan runs full rpm the other complies with the mobo's orders.


    Which motherboard would that be?
  4. Best answer
    BTW, I picked up one of these to control 2 of my 3 pin fans from a single 4 pin header. It will allow the PWM motherboard signal control regular 3 pin fans. It also allows switching to variable DC control via the rheostat. If you are interested, pick one up. But they must be popular, because they are sold out at Newegg and Frozen PC.
    http://www.amazon.com/Sunbeamtech-PL-RS-PCI-Rheosmart-PCI-Controller/dp/B004LL8KF6
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