Question Can not control System Fan

[comertcimen]

Hi, i have msi b450m-a pro max motherboard and can not control system fan speed. I can control cpu fan speed with smart fan but even if i reduce voltage on bios, case fans work at full speed. My previous mobo was gigabyte a320 and i could easily control all fans on gigabyte software. I installed msi dragon center and nothing changed. (case fans are 3 pins not pwm)

 

[drea.drechsler]

...
(case fans are 3 pins not pwm)

Since your fans are three pin.... did you try setting the fan control to be 'voltage controlled' and not PWM controlled? Take it out of AUTO, if it has that option.

Also, for Ryzen 3000 CPU's it may seem you can't control fans as they tend to pulse a lot when the processor's at idle. It's really just low-energy temp spikes as the processor boosts but doesn't really get hot. What I advise is to set a flat fan curve that's a low, barely audible speed, up to about 65-70C then increase fan speed, only getting really loud at about 80-85C.

 

[helpstar]

in which headers of the motherboard did yo plug in the fans?

 

[comertcimen]

in which headers of the motherboard did yo plug in the fans?

To sys fan. Just like i did when i have gigabyte a320

 

[comertcimen]

Since your fans are three pin.... did you try setting the fan control to be 'voltage controlled' and not PWM controlled? Take it out of AUTO, if it has that option.

Also, for Ryzen 3000 CPU's it may seem you can't control fans as they tend to pulse a lot when the processor's at idle. It's really just low-energy temp spikes as the processor boosts but doesn't really get hot. What I advise is to set a flat fan curve that's a low, barely audible speed, up to about 65-70C then increase fan speed, only getting really loud at about 80-85C.

Yes i tried both pwm and voltage options on bios. Nothing changed, still full speed. My cpu is ryzen 5 2600.

 

[helpstar]

manual:
"CPU_FAN1, SYS_FAN1: Fan Connectors PWM Mode fan connectors provide constant 12V output and adjust fan speed with speed control signal. When you plug a 3-pin (Non-PWM) fan to a fan connector in PWM mode, the fan speed will always maintain at 100%, which might create a lot of noise. "

Couldn´t find any setting to alter in BIOS, but that´s the thing. Maybe you have to update the BIOS to a newer version.

 

[comertcimen]

I tried both pwm and dc, temperature source cpu and system fans, smart fan mode on-off and set all voltage to lowest point but nothing changed.

 

[comertcimen]

manual:
"CPU_FAN1, SYS_FAN1: Fan Connectors PWM Mode fan connectors provide constant 12V output and adjust fan speed with speed control signal. When you plug a 3-pin (Non-PWM) fan to a fan connector in PWM mode, the fan speed will always maintain at 100%, which might create a lot of noise. "

Couldn´t find any setting to alter in BIOS, but that´s the thing. Maybe you have to update the BIOS to a newer version.

I have the latest BIOS.

 

[drea.drechsler]

That seems like an awful lot of fan wire bundles going to one header on what looks to be a 3- or 4-way splitter. How many fans do you have hooked to it? Have you tried just one fan all alone, no splitter, to see if it works right?

 

[comertcimen]

That seems like an awful lot of fan wire bundles going to one header on what looks to be a 3- or 4-way splitter. How many fans do you have hooked to it? Have you tried just one fan all alone, no splitter, to see if it works right?

I tried every single fan without splitter one by one, still same, full speed. It is not about splitter because i used it with my previous mobo, there was no problem. I wrote to msi, maybe they can help.

 

[drea.drechsler]

I tried every single fan without splitter one by one, still same, full speed. It is not about splitter because i used it with my previous mobo, there was no problem. I wrote to msi, maybe they can help.

My concern would be the splitter allowed you to overload the controller on THIS motherboard with too many fans at once. I'm not at all sure it would, but maybe the overload simply damaged the controller's ability to adjust voltage to the fans which leaves it at a constant +12V.

 

[comertcimen]

My concern would be the splitter allowed you to overload the controller on THIS motherboard with too many fans at once. I'm not at all sure it would, but maybe the overload simply damaged the controller's ability to adjust voltage to the fans which leaves it at a constant +12V.

Then why the same thing doesn't happen to a worse motherboard?

 

[drea.drechsler]

Then why the same thing doesn't happen to a worse motherboard?

Can't say for certain but it's quite possible it has a controller circuit that can handle the load.

Does your current motherboard have some other fan headers you could try using? Do it with ONE fan only and see if it can control it correctly. I'd not try the three-way splitter again though.

EDIT: naahh...i see all you've got is one sysfan and one cpufan header. the cpu fan almost certainly would control it so no sense in stealing that header.

 

[geraltnaber22]

My concern would be the splitter allowed you to overload the controller on THIS motherboard with too many fans at once. I'm not at all sure it would, but maybe the overload simply damaged the controller's ability to adjust voltage to the fans which leaves it at a constant +12V.

I have the same exact problem. I have the same mobo, latest bios, my fans are 3 pin, but the fan header of the mobo is 4 pin. The manual says 3 pin fans will run at max speed due to constant voltage supplied, but the bios screen has the voltage control setting, it's just not working though. My fans are stuck at 1250 rpm, even if I change the voltage, the speed doesn't change. Did you get a reply from msi? Or have you found another way to control these 3 pin fans?

 

[comertcimen]

I have the same exact problem. I have the same mobo, latest bios, my fans are 3 pin, but the fan header of the mobo is 4 pin. The manual says 3 pin fans will run at max speed due to constant voltage supplied, but the bios screen has the voltage control setting, it's just not working though. My fans are stuck at 1250 rpm, even if I change the voltage, the speed doesn't change. Did you get a reply from msi? Or have you found another way to control these 3 pin fans?

No, I couldn't solve it. If you can find a solution, please write it.

 

[Archimagus]

I have a different but similar problem. In my bios I can set my system fan to DC and it controls just fine, but when windows loads and MSI Center takes over, it seems to revert the fan control as the fan spins up and the graph shows like it does in the OP where the fan spins at roughly 1300RPM no matter the temperature.
Any advice on that?