Question Help setting up (AIO) fan modes in BIOS

abyss010

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Mar 16, 2021
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I have a Corsair H100 AIO and some standard Arctic fans. My motherboard is an MSI Z490

Would anyone be able to advise which modes to set my fans? I am mostly puzzled about my AIO. I can't find much information on this model as it seems most people have the newer ones.

The CPU temperatures are very good, around 38-40c idle (im guessing summer plays a factor) and 65c while gaming but I never actually changed these settings until getting this new AIO, so I would like to confirm it's right as to avoid any damage. I've never had a liquid cooler before.

Currently I have CPU_FAN set to PWM mode and all SYS_FAN set to DC.


CPU_FAN was automatically set to Auto/DC so I changed it to PWM.
Reverting CPU_FAN to DC seems to go right down to 0RPM with no movement, but PWM makes it run at around 3000PM. Is this correct?

Changing some of the other SYS_FANs to PWM results in higher RPM and louder PC. One of the RPM falls lower if changed from DC to PWM (maybe this is the AIO fan, I need to check which one its plugged into).

I have the Corsair pump in CPU_FAN (as instructed) and it's fans in a SYS_FAN header, other case fans are also in SYS_FAN headers.

I believe the pump is 3-pin.

I have "CPU Cooler Tuning" in MSI BIOS set to Water Cooler.

Also, it says "Do not utilize voltage fan control on the CPU_FAN header with the pump connected for the best performance experience." in the AIO online manual but I'm not technically literate enough to understand, so would appreciate an explanation.

Really, I could just be overthinking but hearing some perspective is good
 
Last edited:

Paperdoc

Polypheme
Ambassador
Your mobo manual on p. 61 shows the typical screen for fan header adjustments. At upper right you choose one header at a time to make any changes.

General rule: for any fan with FOUR wires in its cable and ending in a fan connector with FOUR holes, the header it is plugged into should always be set to PWM. Normally for an older 3-pin fan the header should be set to Voltage to DC. BUT the PUMP in an AIO system is special! Its header ALSO should be set to PWM as the Corsair H100 manual says. This uses a quirk of the fan systems to ensure that the pump always runs full speed as designed. The 3000 RPM reading you report sounds right. So you should change this setting for your SYS_FAN headers since all of your fans, I suspect, are the 4-pin type.

Here's another item to adjust. You have the RAD FANS of the H100 system connected to one SYS_FAN header using a small Splitter supplied with them. On the screen for that particular header, note the item at left centre for Temperature Source. Set this to CPU for the rad cooler fans. Set it to Motherboard for all your case vent fan headers. That way the Rad Fans' speeds will be automatically adjusted according to the temperature inside the CPU chip, but he case vent fans' speeds will be adjusted according to a different sensor on the motherboard.

When you have adjusted all your fan headers, use Esc back to Main Menu, then F10 to pop up a confirmation screen. Confirm that it should SAVE your new settings and reboot.