Problems controlling fans while using a pwm fan hub.

Hi Everyone,

I am having a problem adjusting my fan speeds on my computer. The fans are stuck at 100% at all times. I am using the GA-Z170N mini itx and I didn't have enough fan ports on the motherboard so I bought the Silverstone PWM fan hub to connect all the fans together. I am using af120 & sp120 RGB fans to cool my computer. I tried using the Gigabyte fan controller software and the PWM settings in the bios but the fans stay at 100% no matter what. I also tried using a Noctua PWM fans as the PWM fan receiver with the Silverstone hub but the fan still stays at 100%. I also tried just plugging a single PWM fan on the board and I can't control it at all. I'm wondering if you guys have any idea to what might fix this issue.

Thanks, everyone!

Intel Core i7-6700K
Corsair H100i
Gigabyte GA-Z170N
Corsair Vengeance LED
Intel 600p 512GB M.2-2280
Toshiba P300 3TB
MSI GeForce GTX 1080
Fractal Design Define Nano S
Corsair SP120 RGB
SilverStone PWM Fan Hub
Noctua NF-F12 PWM
7 answers Last reply Best Answer
More about problems controlling fans pwm fan hub
  1. The SYS_FAN header on that motherboard is not a PWM header despite having 4 pins. You need a 4-pin splitter cable to connect the hub. Gigabyte likes to use non-standard fan headers for some reason.

    The splitter has two male connectors (go to the fan/hub) and one female connector (goes to the CPU_FAN header). One male connector will be missing a pin. Connect that to the hub, and the one with all four pins to the CPU fan.
  2. Unfortunately that does do anything. Fans still stuck at 100%. I go to pwm to switch and it still isn't working.
  3. Go into BIOS, and in the PC Health Status section, there should be an option for "CPU Fan Speed Control". If that's set to Manual or Full Speed, your fans will not change speed according to temperatures.

    You can set it to Silent or Normal to adjust fan speeds with temperature.
  4. Fan still stuck at 100% unfortunately.. I tried bios and software. What are the chances of the motherboard being faulty and the PWM connection has errors.
  5. Best answer
    What the nerd 389 said is quite correct as far as it goes. Any 4-pin fan Hub MUST have a PWM signal supplied to it on Pin #4 of its mobo header, and your mobo cannot do that from the SYS_FAN header. His / her solution gets the signal from the CPU_FAN header.

    But that's only part of the trouble. The real problem you have is that all those fans you specified are of the 3-pin design. ANY 3-pin fan plugged into a 4-pin port that uses PWM Mode can only run at full speed. The method used by a PWM Mode port to control its fans requires that the fan itself include a special chip that uses the PWM signal from Pin #4 to modify the power supplied to the fan on Pin #2. But 3-pin fans don't have that chip, and hence don't have a Pin #4 to receive a signal they cannot use.

    The only way to control a 3-pin fan is with a fan header that uses Voltage Control Mode (aka DC Mode), which your mobo SYS_FAN header does. HOWEVER, if you are trying to connect several 3-pin fans to that one header, you must use a SPLITTER, not a Hub. A Splitter simply connects all its fans in parallel to the varying-voltage power supplied on Pin #2, and that's how the fans' speeds are changed. BUT there is a limit. Each mobo SYS_FAN header can supply up to 1.0 amps to all its fans in total. With many current fans, that works out to 3 or 4, sometimes even 5 fans as a limit for one header. BUT your have bought fans with LED's built in, too, and those LED's actually use MORE power than the fan motor. So you need to verify carefully the amps rating for each of your fans. Add up the amps of all the fans you want to connect to one header using Splitters, but it must NOT exceed 1.0 amps. Then you can get one or more splitters to set up the connections. IF you want to go this way, post back your choice fro a hint on how to differentiate between Splitters and Hubs.

    There is ONE other option for you if you have more than 2 or 3 of these fans. Get a particular different Hub. Buy the Phanteks PWM Hub. It is different in that, instead of merely sharing mobo's the PWM signal to all its fans (which normally must be PWM type to use the signal), this Hub uses the PWM signal from the mobo header to create its own group of six 3-pin fan ports, each using Voltage Control Mode. That is exactly what you need for your fans. And each of those Hub ports, like mobo headers, can supply up to 1.0 amps, so you can attach six 3-pin fans to this Hub. It gets power for all its fans directly from the PSU via a connection to a SATA Power output, just as your Silverstone unit does. If you connect this Hub's fan line to the output arm of the 4-pin Splitter that the nerd 389 recommended - the one missing one pin - then the Hub WILL receive the PWM signal it needs from the CPU_FAN header, and it WILL power and control the speed of all your 3-pin fans, according to the automatic controls used to cool your CPU chip. You just will NOT see the speeds of any of the Hub's fans displayed anywhere, because there is no way to feed them to the mobo.
  6. Thank you so much paperdoc & nerd389 for helping me finally found the configuration that worked. I went with the Phanteks hub for 3 pins and it fixed the problem right away.
  7. Great! Glad it worked. Thanks for Best Solution.
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