How does Fan Controlling really work?

[dfmastin]

How does Fan Controlling really work?
a) First UEFI/Bios typically offers fan control. Once Windows starts how are the fan speed choices and curves generated in bios/uefi changing fan speeds?
b) Every mobo manufacturer (MSI, Gigabyte, ASUS etc) has a software suite that has a fan tuning option. If you set speeds and curves in the bios/uefi is this mobo manufacturer software conflicting? Does one take priority over the other?
c) Finally, there are open source choices like FanControl that is popular. Is this just an open source variant of the mobo manufacturer software? I read on github:
“Q What setting should I set in my BIOS to play along nicely with FanContor?
A You want to avoid any smart control from your BIOS. Setting a fixed default speed, like 50%, works great for most people. Also keep an eye if your BIOS has PWM or DC mode on. One could work better for you depending on your setup.”
Is this good advice? Can anybody explain a bit what’s going on behind the curtain?

[Jurrunio]

On a motherboard there's an IC that specifically handles fan speed, BIOS and software in OS all work by programming it. Even if you never touch it, there's still factory defaults that it will follow (which is set by the BIOS). After you're done programming it, it will keep on running according to this logic until you shut the PC down.

 

19 minutes ago, dfmastin said:

Does one take priority over the other?

Usually no, whichever made the latest changes will be the one ruling over others.

[manikyath]

a: as far as i'm aware, windows pays no attention to fan speeds, and lets the BIOS settings sort that out.

 

b: depends on the tool. some tools write their settings to bios, some overrule bios.

 

c: software controlling fans is generally "universally applicable" as long as the software can interact with the hardware device that actually does the fan control. there's no "magic" to asus' fan control software that makes it "better with asus", all it does is override whatever the bios is doing with whatever the software thinks it should be doing.

[dfmastin]

9 minutes ago, Jurrunio said:

On a motherboard there's an IC that specifically handles fan speed, BIOS and software in OS all work by programming it. Even if you never touch it, there's still factory defaults that it will follow (which is set by the BIOS). After you're done programming it, it will keep on running according to this logic until you shut the PC down.

 

Usually no, whichever made the latest changes will be the one ruling over others.

very nice and interesting, thank you

[dfmastin]

4 minutes ago, manikyath said:

a: as far as i'm aware, windows pays no attention to fan speeds, and lets the BIOS settings sort that out.

 

b: depends on the tool. some tools write their settings to bios, some overrule bios.

 

c: software controlling fans is generally "universally applicable" as long as the software can interact with the hardware device that actually does the fan control. there's no "magic" to asus' fan control software that makes it "better with asus", all it does is override whatever the bios is doing with whatever the software thinks it should be doing.

i see, ok, thank you that is helpful