Question Fan PWM Compatibility on ASUS B350-F GAMING Mobo

[yksi]

Hi,

I was looking at the manual for my ASUS B350-F mobo in order to figure out the best fan splitting/plugging setup for my water cooled PC.

I have 4 PWM-capable fans, a PWM pump, and a stock case fan (Enthoo Pro M TG) which I am not sure is PWM. From looking at the manual, there are 6 fan headers: CPU_FAN, CPU_OPT, CHA_FAN[1,2,3], AIO_PUMP. However if I'm reading it correctly, only the CPU headers enable PWM, as they are the only 2 headers with PWM pins while the others have simple GND, PWR, IN, +5V setups.

What I was thinking is necessary is plugging my pump into the CPU_FAN header and then getting a 4:1 splitter to use the CPU_OPT for all the PWM fans to spin at the same variable RPM. It seems to me like using the CHA_FAN headers will put them at 100% constantly (which is probably fine for the case fan). Is my understanding correct?

 

[CountMike]

No, don't plug pump in CPU_Fan header, it should go to AiO_pump header and it's probably not speed adjustable which is a norm for such pumps.
Also don't mix chassis and CPU fans, CPU fans only should be adjustable by CPU temps. Mixing PWM and Voltage adjustable (3pin) fans on same header is not a good idea.
3pin fans can be adjustable only by voltage but can also be plugged in a PWM headers, just may need to set it as voltage adjustments in BIOS. Likewise, most PWM fans can be voltage adjustable and controlled like that just fine.

 

[yksi]

Ah ok, thanks. So essentially I can do pump in AIO_PUMP, my 4 PWM fans as 2 in CPU_FAN and 2 in CPU_OPT since they are all PWM adjustable, then chassis fan in any CHA_FAN so I’m not mixing power types on any header?

My pump is EK XRES 140 D5, which has this power paradigm:

• PWM duty cycle: ~ 20-100%
• Default behavior: Runs at 100% duty cycle when no PWM feedback signal is present

Is it still not worth using a PWM pin? If i’m understanding your post right, can V regulation substitute for PMW regulation as long as there is no mixing on the same header?

My 4 fans are all EK-Vardar EVO 120S BB (700-1150rpm), which EK recommends using CPU_FAN for.

 

[CountMike]

Are those 4 PWM fans are on radiator ? If yes then they do belong in CPU_Fan and CPU_opt as those headers are controlled together.

 

[yksi]

Yep there are 2 each on 2 radiators. Thanks for the help!