Question Why is my system fan shown as not spinning in BIOS/HWmonitor after boot, but inside the case all the fans are spinning?

[Pikolo19]

Hello, when i start my pc after shutdown, sometimes the fans go very loud. I checked HWmonitor and it doesn't show my System fan (Fanin1) at all, and temps are also high on idle(60-65 deg on cpu). But in reality all the fans in my pc case are moving. If i restart pc and enter bios the problem is solved, according to bios the temps are back to normal and system fan is moving. When i enter desktop again HWmonitor shows System fan too now, and temps are back to normal. I tried to put manual speed of system fan on 0 in bios to see exactly which fan is it, but they are all moving... and the temp inreases. I am so confused.

PS: cpu fan and system fan are on auto mode in bios. I have 4 fans(3 front and 1 back) in system case and one cpu fan.

 

[iPeekYou]

Funky BIOS behavior? I'd try resetting defaults on BIOS and/or replacing the CMOS battery. Similar but unrelated: sometimes when I change my fan curve offset in BIOS (as in the tolerance between reading and fan curve), my BIOS states there's a failure to boot to BIOS that I solve by entering BIOS, redoing that change, and booting up normally.

Is there any Windows software that might interfere with fan curve? Like SpeedFan or motherboard manufacturer's software maybe?

 

[Pikolo19]

Funky BIOS behavior? I'd try resetting defaults on BIOS and/or replacing the CMOS battery. Similar but unrelated: sometimes when I change my fan curve offset in BIOS (as in the tolerance between reading and fan curve), my BIOS states there's a failure to boot to BIOS that I solve by entering BIOS, redoing that change, and booting up normally.

Is there any Windows software that might interfere with fan curve? Like SpeedFan or motherboard manufacturer's software maybe?

I dont have any software like that, and my mobo is h310m h. All settings on bios are on default and bios is updated... i dont get why even hwmonitor is saying that fan is not spinning but in reality it is. Bios is saying too that is not spinning, but when i enter fan settings in bios the fan rpm starts to increase. Very strange.. basically i have to enter bios every time after i boot my pc in order to start the fan.. but in reality the fan is spinning all the time.

 

[iPeekYou]

I dont have any software like that, and my mobo is h310m h. All settings on bios are on default and bios is updated... i dont get why even hwmonitor is saying that fan is not spinning but in reality it is. Bios is saying too that is not spinning, but when i enter fan settings in bios the fan rpm starts to increase. Very strange.. basically i have to enter bios every time after i boot my pc in order to start the fan.. but in reality the fan is spinning all the time.

Yeah I get ya. Still, it can't hurt to just select reset optimized defaults and go from there.

Another question: how are the four fans connected to the motherboard? Depending on the fans' power draw, could be that you're slightly overloading the header if all 4 are connected to the same header.