MSI Z490m (Meg Infinite x 10th motherboard) : Sys_fan 3 issue

charles.garrec

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Hello !
I need some help/advice as I want to add an additional fan in a Meg Infinite x 10th computer.
I purchased a Scythe Kaze Flex 120mm fan and when I plug it in the sys_fan 3 pin connector on the motherboard, the fan is at maximum speed (1200 rpm).
When I go in the BIOS (vers EB916IMS), I see the fan in the hardware monitor at 1200rpm , selected as PWM (no DC/PWM choice), and what ever I choose (auto fan) or manual fan curve, the fan sticks at 1200 rpm.

The current fan setup in this computer is :
1 CPU/Pump 120mm fan (msi watercool)
1 Exhaust 120mm fan on top of the case.
1 Intake 80mm fan in the front panel for the GPU section on the case)

Has anybody encountered this bug and knows how to fix it ?

Thanks in advance !

(PS : I tested this fan on another computer with an asus z170 Pro Gaming and the fan is properly recognized and the idle fan speed is automatically set at 400rpm and not at full speed like on the MSI Z490m).
 

fatedust

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Use the 3 to 4-pin power adapter which comes with the fan and connect it to the sys_fan 3 pin connector.
 

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charles.garrec

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Use the 3 to 4-pin power adapter which comes with the fan and connect it to the sys_fan 3 pin connector.
Argh fudge, that fan has only a 3 pin connector.

I wonder why on my Asus m170 Pro Gaming motherboard the fan with it's 3 pin connector is connected on the motherboards' 4 pin CHA_FAN connector and the Bios can control the fans' speed.

Is it something specific to the MSI Boards ?

@Teletubby_pro : the bios re-installation had no effect :(
 

fatedust

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MSI board: Since it's on PWM mode, and your fan only has a 3-pin connector, which means Ground, +12V, and Sense these 3 pins are connected. But the last pin for Speed Control Signal is not. So that's why you can't control the speed and it keeps spinning at max.

ASUS board: GND (Ground), CHA FAN PWR, and CHA FAN IN (Sense) are connected, so the only difference is the power input. I'm not sure how ASUS does but it seems to use the CHA FAN PWR pin to control the fan's speed.
 

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charles.garrec

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Aaaaaah ok, that makes sense !
I guess that using the daisy chain 3pin/4pin molex adapter won't help in anything and will just have the fan run at max rpm ?

So only option left is to find a 4pin PWM fan, argh.
Honestly this pc is really great but the sound the 2080Ti makes is really the big let down ... If only it could be quieter :(
 

charles.garrec

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Feb 28, 2014
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The problem is that in the BIOS (latest version), I do not have the choice between DC and PWM.
When I select a fan (Sys_fan1, Sys_fan2, Sys_fan3or even CPU_Fan) I only have PWM selected and no other choice.
Anyway I ordered two Noctua 4 Pin fans (a9 and a12 : a9 to replace the 90mm front intake in the GPU section; a12 to add to the front panel for additional intake)

Still trying to figure out which is best for silence / heat :
Leaving the glass panel that has a 2cm gap all around it or putting the case panel that has ventilation holes in front of the vertical GPU ...
 
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