Trouble with fan control

[Padlorr]

Hi, I have a Crosshair V Formula system with multiple case and chassis fans and an H80i cooler (DC fans). I've connected the H80i to the CPU fan controller but I've noticed that the rpm's never ramp up or down based on cpu load/temps - it just stays around 2250rpm regardless. I heard that the cpu headers only control 4 pin (PWM) fan speeds, and the Chassis fan headers are the only ones that can control 3 pin fan speeds, is that correct?

I also have some 3 pin case fans connected to Chassis headers because the OPT headers won't ramp their speed in "User Mode" based on cpu temps. I can control their speed in Duty Mode but that only allows for one speed. Should the OPT headers be able to control 3 pin fan speed in User Mode based on cpu temps or do I need thermal sensors connected for that?

Any advice would be great!

[Arne_Saknussemm]

Hi Padlorr 🙂

For temp sensitive feedback for the fans you need 4 pin PWM. Any 3 pin fans will not follow fan profiles on CPU or opt headers. The duty mode or Profile modes will control most 3 pin fans based on voltage.

The pump of the H80i does run at constant speed as far as I know....it is not controlled by the motherboard....maybe you can controll it via corsair link usb connection. Connected to the CPU header it just gives RPM signal to motherboard so the MB knows it's running and will boot.

[Padlorr]

Thank you. The Chassis Fan headers actually do control speeds for these 3 pin fans, but the OPT fan headers do not. I don't see any profiles other than User or Duty modes. In any case, I've moved these fans back to the OPT headers to reduce the noise by setting them to 50% Duty mode (they wind up very high when connected to the Chassis headers even at idle or lower loads).

As far as the H80i pump is concerned, that's what I thought, but I'm wondering where to monitor and control the H80i radiator fans. (Must be from CorsairLink which I find to be very clunky). I had assumed that the CPU Q-Fan control would be controlling those too.

[samual]

Don't know if your board has the same setup in bios as my M5F. But go into monitor, advanced mode, set the q-fan to manual and change the settings. I found I required a higher speed at lower temps.

[Padlorr]

Thanks samual, I have played around with the settings (disabled, standard, turbo or silent) in there. I"ve noticed it can make a difference with the PWM chassis fans at lower loads.

[Chino]

If you want to control the H80i fans via the motherboard, first you have to connect the pump to the CPU_OPT header. Since the pump's speed doesn't vary, it'll always be running at 100%. Secondly, you connect the H80i's fan to the CPU_FAN header to have them controlled by temperature (assuming the H80i's fan is a 4 pin/PWM fan).

I'm not familiar with the number of fans that came with your H80i or their power draw. The motherboard fan header can support up to 1A. So for precaution's sake make sure your fan doesn't pull more than that before you connect it to the header.

[Padlorr]

Thanks Chino, unfortunately my H80i was part of the last batch that came with DC fans. They're pretty loud and I'm not sure they're being controlled based on cpu temps. I have mostly plugged it into the CPU_FAN header. I've tried it on the CPU_OPT header once and didn't notice a difference, but I'll try again and see if it provides additional control options. Which header do you recommend for DC fans? For the CPU fans, I'd like them to be controlled by cpu temps.

I believe the H80i is also connected to another PSU cable so I'm pretty sure it's getting all the power it needs for the pump and dual radiator fans. It's a pretty sweet system, I'm just not 100% sure it's working perfectly due to the noise and high core temps (up to 63 C) I'm getting with my 4.5-4.6ghz OC attempts (with a corresponding 76 C cpu temp). So I'm keeping my eye on it, but those temps may be normal for the FX-8150 at those speeds (I'm just not sure). I'm also possibly overvolting my CPU/NB by keeping it on auto as I've been unable to get it stable at these speeds otherwise, and that may be driving up my temps.

[Padlorr]

Thanks Chino, unfortunately my H80i was part of the last batch that came with DC fans. They're pretty loud and I'm not sure they're being controlled based on cpu temps. I have mostly plugged it into the CPU_FAN header. I've tried it on the CPU_OPT header once and didn't notice a difference, but I'll try again and see if it provides additional control options. Which header do you recommend for DC fans? For the CPU fans, I'd like them to be controlled by cpu temps.

I believe the H80i is also connected to another PSU cable so I'm pretty sure it's getting all the power it needs for the pump and dual radiator fans. It's a pretty sweet system, I'm just not 100% sure it's working perfectly due to the noise and high core temps (up to 63 C) I'm getting with my 4.5-4.6ghz OC attempts (with a corresponding 76 C cpu temp). So I'm keeping my eye on it, but those temps may be normal for the FX-8150 at those speeds (I'm just not sure). I'm also possibly overvolting my CPU/NB by keeping it on auto as I've been unable to get it stable at these speeds otherwise, and that may be driving up my temps.