Arcfic F12 fan

[DarkWater]

While I'm visiting this forum to get some insight into an issue posted on another forum section, I may as well ask something that has been puzzling me. It is in regards to my Arctic F12 fan.

 

It is a 3-pin fan and I thought these fans could not be controlled (unless in voltage mode) and instead just ran at full power all the time. I set a fan curve for this fan just to see what happens. I did this on both the BIOS and also via Asrock A-Tuning utility on Windows. As expected, nothing happened at first. It just ran at full RPM all the time. That was until I learned that for some reason, it usually takes 2 system boot ups for the fan curves to actually get applied (just this fan only). The fan follows what I set and adjusts its RPM according to the CPU temperature, instead of running at full RPM.

 

So to get that fan to obey the fan curve, I have to power the machine on once (it runs at full blast and ignores the fan curve on the 1st power up). Once it's on the Windows login screen, shut down and then power on again. Immediately on the second boot, I will hear the fan slow down to whatever the BIOS is telling it to run at. It then adjusts again when it enters Windows (to match what A-tuning says, as it's slightly different). I usually only have to do two system boots if the system has been off for some time. There is an off-chance where I won't need to do 2 boot ups.

 

Any idea what's happening here? My motherboard is the Asrock Z170 Extreme4. 

 

 

[Jurrunio]

Minor bugs that go unfixed lol

 

my guess is Asrock forgot to make the BIOS load the fan settings during first boot after clear CMOS. they probably jkust missed a line of code.