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I have 2 large fans in my case it's mATX case the key components are:

Asus H97M-E Motherboard &
Hydro Series™ H55 Quiet CPU Cooler

Now the motherboard has 3 (4 pin) connectors for CPU Fans and 2 extra fans. 2 pins are taken by the water cooling system and one pin is taken by the default fan that came with the case.

Everything works fine however the BIOS is showing fans spinning at 1500-1600 RPM pretty much at maximum and the CPU is not even being overloaded it's at cool 23*C which is pretty low for new gen top level i7.

In BIOS I set all my fan control settings to Silent but these fans are going all wild no effect only thing is if I moved the fan settings from DC to PWM they go crazy they speed up even more and get even louder. I mean the PC case is now so freaking cold to the touch.

1 More thing the motherboard did come with a controller/device that allows you to throttle the fans at the back of the pc it has 4 cables two go to power unit the and two are male connectors where fans connect but they are (2pin) where as fan connector are female (3pin) but this can't be the way to control fans can it ?

Solution:

I had wrongly connected the cables. Basically with water cooling system you get two cables one from the head that goes on top of CPU (pump) and one that is for the cooling system fan. On my motherboard I have 3 FAN Connectors however 1 is named CPU_FAN previously I had the pump connected to the CPU_FAN and the cooling system fan connected to FAN1 connector.

You have to connect the cooling system FAN to CPU_FAN and you connect pump to any other connector for me it was the 4 pin FAN1 connector. After that PC only get's a bit loud for few seconds after boot or very heavy loads.

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    Sounds like your not using the correct power cable which provides the capability to tune the fan speed you can either use the correct power cable I'd your hardware supports or or use a quiter fan – Ramhound Nov 4 '14 at 19:33
  • @Ramhound How can I on motherboard all CPU FAN pin connectors are 4 Pin connectors the case Fan and the Hydro cooler fan both have 3 Pin connectors : / – Sterling Duchess Nov 4 '14 at 19:36
  • Have you installed "Fan Xpert 2+" (I think you have to install Asus AI Suite 3 to get it) and found the part which calibrates the fans? The motherboard 4-pin fan connectors also accept 3-pin fan connectors - just have a good look at where the tab is on the motherboard connector (a bright torch can be handy) and be careful plugging them in. – Andrew Morton Nov 4 '14 at 20:32
  • dunno but what if you remove the hardware fan control? – barlop Nov 4 '14 at 20:51
  • Is this a pic of what the options look like in your BIOS? i.stack.imgur.com/uwdxz.jpg kmpic.asus.com/images/2014/06/19/… – barlop Nov 6 '14 at 3:18
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PWM control requires that fourth pin on the header. Since your fans only have 3 pins, they are not PWM capable, which is why they go to full speed when you set the bios to use PWM. 1500-1600 rpm is probably close to the minimum speed the fan can operate at. The only way to get it quieter is to stop it completely, which I'm guessing your motherboard is not willing to do, no matter how cool things are. At that low speed though, they should be pretty quiet.

If they are still that noisy then they must just be bad fans and you need to replace them, preferably with PWM capable 4 pin units.

  • It says on the box that minimum RPM for 200, maximum setting is 2000. For Hyrdo CPU cooler has minimum 300 RPM and maximum 2525 RPM . When I turn on the PC the fans kick in at top setting in DC mode which is ~1500 RPM if I switch to PWM even tho its 3 pins not 4 pins I see them go up the case fans go to 1980-2000 and cpu fan goes to like 2200 – Sterling Duchess Nov 4 '14 at 20:40
  • -1 I don't think your first sentence is true. I think it isn't true. 3pin CPU fans have been PWM controlled by the MBRD long before PWM fans came out.. And in theory, 2 pin case fans could be too as the third pin RPM, isn't PWM related, it just reports RPM to the MBRD for failure detection. The difference is whether the PWM Circuit is in the motherboard (as with the 3 pin CPU fans we've used over the years), or the PWM circuit is in the fan, as in the 4 pin fans which get a PWM signal and choose whether to honour it. – barlop Nov 4 '14 at 20:59
  • And yet it was. I tracked down the problem. Near CPU I have 3 Fan connectors however one is white and is named CPU_FAN other two are named FAN1 and FAN2. All are 4 pins, however what I have done is I have connected the Cooler pump to CPU_FAN and the Fan for the water cooler to FAN1. After I switched around the cooler fan was loud only for about 4-5 seconds with the initial boot after that is was super quiet. – Sterling Duchess Nov 4 '14 at 21:54
  • @SterlingDuchess - you should put that as an answer and accept. I guess this is why the basic questions should always be checked first...is it plugged in? is it plugged into the right xxx :) – Carl B Nov 5 '14 at 0:16
  • @barlop, when the circuit is in the fan it is called "pwm"... when it isn't it is called "dc". While both end up ultimately having a counter/timer doing pulse width modulation, you talk about it from the perspective of the fan. – psusi Nov 5 '14 at 14:29
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I've found a lot of motherboards to not work as expected when it comes to speed management of fans. I use Noctua P-12 case fans. They are ever so quiet anyway, however my motherboard can't seem to control them no matter what (despite they are designed to be controlled).

Your controller sounds weird in my opinion, also. Have you tried any PC software to control it? I know H/W Monitor is pretty good.

As a final solution, you may want to invest in a separate fan controller that you could mount into the front bay of your PC.

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I had wrongly connected the cables. Basically with water cooling system you get two cables one from the head that goes on top of CPU (pump) and one that is for the cooling system fan. On my motherboard I have 3 FAN Connectors however 1 is named CPU_FAN previously I had the pump connected to the CPU_FAN and the cooling system fan connected to FAN1 connector.

You have to connect the cooling system FAN to CPU_FAN and you connect pump to any other connector for me it was the 4 pin FAN1 connector. After that PC only get's a bit loud for few seconds after boot or very heavy loads.

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