Manual fan control via BIOS: what do these values mean?

Hardware Hub Cooling
1

While I was optimizing the cooling in my computer case via the BIOS, I came across an option to specify the fan speed on each fan header on my motherboard (Gigabyte GA-Z97X-UD3H). It lets me choose between "normal", "silent", "full speed" and "manual". When I pick "manual", I can access a new field below where I assume that I can pick the fan curve.

The following options are possible from the drop-down menu:

  • PWM 0.75/°C
  • PWM 1.00/°C
  • PWM 1.25/°C
  • PWM 1.50/°C
  • PWM 1.75/°C
  • PWM 2.00/°C
  • PWM 2.25/°C
  • PWM 2.50/°C

Now what do these values mean? I checked my motherboard's manual [PDF], but it doesn't say much about this. The only thing they mention is this:

I assume that it controls the duty cycle of the PWM controller and I am guessing that it might be percent per degree Celsius. But what does that even mean?

2

unfortunately, there's no real standard. You're right in thinking that it correlates with duty cycle, but you'll have to dig through documentation or contact your manufacturer for more detailed info. Try emailing their service team with an inquiry. They might be surprisingly forthcoming.

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