water cooling 4 pin PWM water cooling pump on motherboard fan header designed for that: DC vs PWM mode different performance?

[Vitalius]

I have this motherboard:
https://www.asrock.com/mb/AMD/Fatal1ty AB350 Gaming-ITXac/index.asp

Here is the manual:
http://asrock.pc.cdn.bitgravity.com/Manual/Fatal1ty AB350 Gaming-ITXac.pdf

I have this pump:
https://www.ekwb.com/shop/ek-ddc-3-2-pwm-laing-ddc-3-2-pwm


It is now wired like this:


Going out to this:


So ending up like this on the motherboard (sorry about it being dark):


Now this motherboard supports doing this as it says in the manual:


Which is what the specifications for that pump are, as listed on the site:

Quote

Technical Specifications:
- Dimensions (W x D x H): 90 x 62 x 38 mm
- Motor: Electronically commuted ball bearing motor
- Rated voltage: 12 V DC
- Power consumption: 18 W
- Maximum head pressure: up to 5.2m
- Maximum flow rate: up to 1000 L/h
- Maximum liquid temperature: 60 °C
- Materials: Stainless steel, PPS-GF40, EPDM O-rings, Aluminium oxide, hard coal
- Power connector:  4-Pin Molex- and 4-Pin PWM FAN connector

And in the manual, it says this:

 

In the BIOS, I have these options:

 

I've switched it to W_PUMP, and set it to PWM Mode, but when I do this, it is stuck at 100% speed at all times. In the manual, it says this:


If I choose DC mode, it barely runs the pump at all (10-20% speed I guess). I can hear/feel it running, but it's so slow that my CPU gets up to 50-60C on idle. 

I want to control this pump with PWM, but it doesn't respond to any settings I give it in BIOS.

What are these two different modes and why are they interacting with this pump in this way?

[Jurrunio]

use PWM and put it on water pump mode

 

DC mode reduces voltage from 12v at full load to vary the pumps power, while PWM mode turns the pump on and off to control its speed. PWM preferred for pumps because it keeps the torque of the pump high and speed control smooth, while DC mode will be like 'no speed at 30%, 50% speed at 50%', for example

[Vitalius]

8 minutes ago, Jurrunio said:

use PWM and put it on water pump mode

 

DC mode reduces voltage from 12v at full load to vary the pumps power, while PWM mode turns the pump on and off to control its speed. PWM preferred for pumps because it keeps the torque of the pump high and speed control smooth, while DC mode will be like 'no speed at 30%, 50% speed at 50%', for example

Cool, so, my problem is that the two modes don't work as expected. PWM keeps the pump at 100% even when I set the performance curve. DC keeps the pump at 20-30% regardless of settings.

[Jurrunio]

32 minutes ago, Vitalius said:

Cool, so, my problem is that the two modes don't work as expected. PWM keeps the pump at 100% even when I set the performance curve. DC keeps the pump at 20-30% regardless of settings.

Maybe a BIOS update will help? Asrock BIOS arent the best

[Vitalius]

11 minutes ago, Jurrunio said:

Maybe a BIOS update will help? Asrock BIOS arent the best

Fully updated.