PWM header

[nav_kundra]

Hi there. I have an GA-EP43-DS3 and the system fan 2 PWM header will not start my PWM fan. The CPU header however will start the same fan.
Any ideas?

Thanks

[Lsdmeasap]

Re: PWM header

That connection SysFan_2 is controlled via a on-board PWM controller, so it may not be best to use a PWM Fan on this controller. Could be why it will not function

[profJim]

Re: PWM header

The SysFan_2 on my mobo only powers my fans to 45% - 55% of the fan's rated full speed.
Fans that don't under-volt well (i.e. less than about 9 - 10 volts) won't spin up.
This appears to be a common design feature on GB mobos. Why? I don't know.

[profJim]

Re: PWM header

That connection SysFan_2 is controlled via a on-board PWM controller

Makes sense, but I have PWM disabled in my bios.

[nav_kundra]

Re: PWM header

The PWM works off the CPU header so I don't think its disabled. Or whether I have that option in my BIOS, I've tried ctrl+F1 but get no additional options.

Lsdmeasap - is there anyway to modify the operation of the onboard controller?

[dbee]

Re: PWM header

I thought The only Mobo header with PWM was the cpu fan header and the connecting fan had to have the extra wire (i think its blue) since the stock i7 cpu cooler has this , but my noctua cooler does not. So the Scythes i have on my cpu cooler are always running full speed.

It might be nice if i could quite those down from time to time.

[gymenii]

Re: PWM header

Hi there. I have an GA-EP43-DS3 and the system fan 2 PWM header will not start my PWM fan. The CPU header however will start the same fan.
Any ideas?

Thanks

Sys_Fan2 Max is 5v. Fans requiring more volts/amps will not operate.

The PWM works off the CPU header so I don't think its disabled. Or whether I have that option in my BIOS, I've tried ctrl+F1 but get no additional options.

There are no control options for Sys_Fan2 in Bios.

I thought The only Mobo header with PWM was the cpu fan header and the connecting fan had to have the extra wire (i think its blue) since the stock i7 cpu cooler has this , but my noctua cooler does not. So the Scythes i have on my cpu cooler are always running full speed.

It might be nice if i could quite those down from time to time.

A three pin fan can be used on the CPU PWM header. You must choose the voltage setting in bios under cpu fan control in order to control fan speed correctly. If you leave it set for Auto you fans will spin 100%.

[dbee]

Re: PWM header

Sweet , thanks Gymenii. Does this voltage setting apply to all the mobo fans such as the pwr fan and the rest of the cpu fan headers? I would assume it does... I have not seen this option in the bios, maybe i haven't looked close enough. We will find out soon enough tonite.

[gymenii]

Re: PWM header

Sweet , thanks Gymenii. Does this voltage setting apply to all the mobo fans such as the pwr fan and the rest of the cpu fan headers? I would assume it does...

No, just CPU.

I have not seen this option in the bios, maybe i haven't looked close enough. We will find out soon enough tonite.

I don't have your MB, so not sure exactly where it is, but most newer GB MB's have this option.

Edit: In BIOS, it's located in PC Health Status

Edit2: From X58-xxx manual;

CPU Smart FAN Mode: Specifies how to control CPU fan speed. This item is configurable only if CPU Smart FAN Control is set to Enabled.

Auto - Lets BIOS autodetect the type of CPU fan installed and sets the optimal CPU fan control mode. (Default)

Voltage - Sets Voltage mode for a 3-pin CPU fan.

PWM - Sets PWM mode for a 4-pin CPU fan.

Note: The Voltage mode can be set for a 3-pin CPU fan or a 4-pin CPU fan. However, for a 4-pin
CPU fan that is not designed following Intel PWM fan specifications, selecting PWM mode may not
effectively reduce the fan speed.

Good Luck