CPU_FAN and AIO - fans spin on boot then stop

Kenai

Kenai

Kenai

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Joined
5 Apr 2009
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Hi, bit of a problem that my Google skills are failing me for...

I have a Gigabyte B550 AORUS Elite AX V2, Ryzen 5600X with an EK 360 All In One DRGB Cooler.

AIO pump on CPU_OPT, 3 fans on CPU_FAN via supplied 3 way splitter cable.

The trouble I'm getting is that the 3 fans spin up to full speed on boot and then stop. Beyond boot, I can't get them to spin up via SmartFan in Gigabyte SIV or SmartFan in the BIOS.

The PC seems to recognise that there is a fan of some description as it shows a fan symbol in the SIV SmartFan page, rather than a '?' as it does for the SYS_FAN headers that have nothing connected.

I've tried removing the splitter in case that's preventing some sort of speed feedback signal that would cause issues but the symptoms are identical whether 1 fan direct or 3 via splitter.

AIO pump via CPU_OPT behaves as I would expect, controls adjustable in software and BIOS and it responds when adjusted (though I'm leaving it as full speed fixed, read the pump isn't really meant to be speed controlled).

I've tried turning off AMD Cool and Quiet as per one suggestion I found in the BIOS but no difference.

When using 'Calibrate' in SmartFan, the SYS_FAN3 connected case fans ramp up and down but zero reaction from CPU_FAN.

I'm hoping I've missed something daft here, as it's been a good few years since my last build but this is quite frustrating.
 
What fans are they? Usually shouldn't affect it but have you made sure the header is in the right mode, DC or PWM?

And for the sake of it, maybe test one of the fans on one of the SYS_FAN headers just in case it's the CPU header messing up. Maybe a BIOS update too if possible.
 
They're the 120mm EK Vardar DRGB PWM that come with the AIO Cooler.

www.overclockers.co.uk

EK Water Blocks EK-AIO 360 D-RGB All In One CPU Water Cooler - 360mm

Order EK Water Blocks EK-AIO 360 D-RGB All In One CPU Water Cooler - 360mm now online and benefit from fast delivery.
www.overclockers.co.uk www.overclockers.co.uk

Header is in 'Auto' in BIOS. I will try setting to PWM directly.

I'll try and hook one up to a SYS_FAN header, though the fact they all spin up for a few seconds on boot would suggest the fans themselves are functional.
 
So, changing to PWM rather than Auto hasn't changed the behaviour.

Plugged one into SYS_FAN, behaves as expected, adjustable via software etc.

I suppose the lazy option is just run all the fans off a SYS_FAN header instead but still... It should work on CPU_FAN and I want to know why it doesn't :p
 
Kenai said:
Hi, bit of a problem that my Google skills are failing me for...

I have a Gigabyte B550 AORUS Elite AX V2, Ryzen 5600X with an EK 360 All In One DRGB Cooler.

AIO pump on CPU_OPT, 3 fans on CPU_FAN via supplied 3 way splitter cable.

The trouble I'm getting is that the 3 fans spin up to full speed on boot and then stop. Beyond boot, I can't get them to spin up via SmartFan in Gigabyte SIV or SmartFan in the BIOS.

The PC seems to recognise that there is a fan of some description as it shows a fan symbol in the SIV SmartFan page, rather than a '?' as it does for the SYS_FAN headers that have nothing connected.

I've tried removing the splitter in case that's preventing some sort of speed feedback signal that would cause issues but the symptoms are identical whether 1 fan direct or 3 via splitter.

AIO pump via CPU_OPT behaves as I would expect, controls adjustable in software and BIOS and it responds when adjusted (though I'm leaving it as full speed fixed, read the pump isn't really meant to be speed controlled).

I've tried turning off AMD Cool and Quiet as per one suggestion I found in the BIOS but no difference.

When using 'Calibrate' in SmartFan, the SYS_FAN3 connected case fans ramp up and down but zero reaction from CPU_FAN.

I'm hoping I've missed something daft here, as it's been a good few years since my last build but this is quite frustrating.
Click to expand...
My question is why do you want to run them all off the cpu fan header and not on their own sys headers?

If you just want more fans as you have no sys headers left then get a fan hub?
 
VortexA1 said:
My question is why do you want to run them all off the cpu fan header and not on their own sys headers?

If you just want more fans as you have no sys headers left then get a fan hub?
Click to expand...
Because I had made the assumption that the fans dedicated to the CPU cooler would be better to run from the CPU_FAN header, with the SYS_FAN headers used for general case ventilation fans. They would then (if it worked) run on a profile based on the CPU temp, whilst the SYS_FAN headers can be profiled against general case temps.

Regardless, whether one fan or three are connected to the CPU_FAN header, the behaviour is identical.

Connecting to SYS_FAN and throwing in hubs feels like a bodge that's avoiding figuring out why the CPU_FAN header isn't working correctly in the first place.
 
Kenai said:
Because I had made the assumption that the fans dedicated to the CPU cooler would be better to run from the CPU_FAN header, with the SYS_FAN headers used for general case ventilation fans. They would then (if it worked) run on a profile based on the CPU temp, whilst the SYS_FAN headers can be profiled against general case temps.

Regardless, whether one fan or three are connected to the CPU_FAN header, the behaviour is identical.

Connecting to SYS_FAN and throwing in hubs feels like a bodge that's avoiding figuring out why the CPU_FAN header isn't working correctly in the first place.
Click to expand...
Ok in your bios you must have fan controlling there. On my mobo I have options on each sys fan to either be controlled based off the cpu temperature or other zones separately all in their own individual header.

I have all of them with a curve based on the cpu temperature in their own headers .you must have that surely so from that you could run them all off a Sys fan controlled by cpu temp? or individually.
 
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Yes, I could do that.

But that doesn't resolve why the CPU_FAN header isn't working correctly with any fans, which is the problem I'd like to understand and hopefully solve, rather than just bypass.
 
Kenai said:
Yes, I could do that.

But that doesn't resolve why the CPU_FAN header isn't working correctly with any fans, which is the problem I'd like to understand and hopefully solve, rather than just bypass.
Click to expand...
Going to suggest something as a test to see if your fans/header are working. I've got the non rgb ek 360 and it's set up with the fans on the cpu header (3 pin splitter) and pump on the pump header (msi motherboard).

Download fancontrol and you should be able to easily adjust fan speeds etc for the header to speed up the fan etc.

Quick guide from JayTwoCents
www.youtube.com

Everyone NEEDS this FREE piece of software... You will thank me!

Learn more about the Corsair XENEON Gaming Monitor at https://www.corsair.com/lm/en/blog/xeneon-gaming-monitorCheck out FanControl for free here! If you like...
www.youtube.com www.youtube.com

Assuming the fans spin up etc then the odds are it's a bios setting issue rather than the motherboard pins etc.

If it is bios have you checked things like which sensor is being used for the temperature reading, the ek fans have a zero rpm mode and if the sensor is reading below the min temp for fans to spin then they won't spin, and then there's things like the fan curves too.
 
I'll try that software if/when I get chance during the weekend (weather being nice, I might not get away with hiding away fixing the PC!), though I'm not holding out too much hope that it's likely to do anything Gigabytes own fan control software isn't or can't do. As I've tried to adjust and control within the BIOS and the software based fan control already. I'll try it nonetheless, as it could shed light on things.

I'll double check all the curves etc. but 99% sure I'd disabled any zero speed modes.
 
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