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

Jun 1, 2021
9
0
20
1
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

Distinguished
Jul 7, 2014
394
77
18,790
10
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?
 
Jun 1, 2021
9
0
20
1
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

Distinguished
Jul 7, 2014
394
77
18,790
10
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.
 

ASK THE COMMUNITY