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PSU fan keeps turning on and off at idle

AusWolf

AusWolf

Joined
Jan 14, 2019
Messages
15,783 (6.86/day)
Location
Midlands, UK
System Specs
System Name My second and third PCs are Intel + Nvidia
Processor AMD Ryzen 7 7800X3D @ 45 W TDP Eco Mode
Motherboard MSi Pro B650M-A Wifi
Cooling be quiet! Shadow Rock LP
Memory 2x 24 GB Corsair Vengeance DDR5-4800
Video Card(s) PowerColor Reaper Radeon RX 9070 XT
Storage 2 TB Corsair MP600 GS, 4 TB Seagate Barracuda
Display(s) Dell S3422DWG 34" 1440 UW 144 Hz
Case Corsair Crystal 280X
Audio Device(s) Logitech Z333 2.1 speakers, AKG Y50 headphones
Power Supply 750 W Seasonic Prime GX
Mouse Logitech MX Master 2S
Keyboard Logitech G413 SE
Software Bazzite (Fedora Linux) KDE Plasma
Hi guys,

I have a Seasonic Prime GX-750 (750 W Gold) in my main rig. I've noticed that its fan keeps turning on and off when the system is idle. I know this because it gives a very quiet, but audible rattle when it starts up, which I don't hear when I turn off its fan stop feature. According to the official website, the fan shouldn't turn on below 300 W power consumed by the PC and there is no way my system eats that much at idle (specs in my profile). There must be something else triggering the fan to turn on and off, but what? Maybe temperature? Or is it faulty?

Any ideas?
 
We can start with two basic questions:

  • What are the loads on the CPU and GPU at idle?
  • What is the internal temperature of the case at idle?
 
cvaldes said:
We can start with two basic questions:

  • What are the loads on the CPU and GPU at idle?
  • What is the internal temperature of the case at idle?
Click to expand...
  • CPU around 1-3%, GPU around 0-1%. According to HWInfo, the CPU eats about 9-12 Watts, the GPU 8-9 Watts.
  • That's a good question. The PSU is housed in a separate compartment with its own "breathing holes" but no direct airflow. Are Seasonic PSU fans triggered also by temperature besides power?
 
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Reactions: Lei
Are Seasonic PSU fans triggered also by temperature besides power?
Click to expand...
The majority, if not all, are triggered by temperature, not the power being drawn.

If it's not the overall temperature of the case or the PSU, then your unit might have a faulty temp sensor, which is triggering the auto fan function. I'd recommend leaving the fan on all the time if there's a button to do so.
 
Udyr said:
The majority, if not all, are triggered by temperature, not the power being drawn.

If it's not the overall temperature of the case or the PSU, then your unit might have a faulty temp sensor, which is triggering the auto fan function. I'd recommend leaving the fan on all the time if there's a button to do so.
Click to expand...
If that's the case, then it might be internal temps in the PSU. I don't hear the fan turn on straight after a cold start - some time has to pass before it starts doing it.

As I mentioned, there is no airflow pointing at it because it sits in its own compartment within the case, so its internals might just get warm enough for the fan to turn on even at idle. Maybe I'll have to test this theory with another fan pointing at it, but for now, I'll just leave the fan on at all times as you said.
 
To my knowledge, Seasonic PSUs are configured to turn on the fan based on either the power draw or temperature.
 
Nothing to worry about its doing what its supposed to do lol if its turning on that is because it is hitting its threshold it will be based on TDP so it knows exactly when it need to turn on it also won't be 40% of 750w either it will be 40% out of 100c because we are talking about themals not watts even though there is correlation between to two.

EDIT:
Sorry i kind of said that incorrectly it will be TDP based so a fulcrum point where the two meet thermodynamics and watts when the PSU gets to that point it turns the fan on, if the fan is on its because it needs to be on.

The only time i would be concerned is if it switched constantly while doing nothing on the PC.
 
Last edited:
AusWolf said:
As I mentioned, there is no airflow pointing at it because it sits in its own compartment within the case
Click to expand...

Is there a way to fix that? if it has just a little wind from the case fans, it would probably be fine at idle.
 
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If possible just turn off hybrid fan feature so the fan runs at minimum all the time. I know both my Seasonic-platform Phanteks and my CWT Thermaltake have switched to make the fan run all the time.
 
Shrek said:
Is there a way to fix that? if it has just a little wind from the case fans, it would probably be fine at idle.
Click to expand...
Not in this case, no. :( It sits right next to the back wall of the case with its own breathing holes (Corsair 280X).

REdebb said:
The only time i would be concerned is if it switched constantly while doing nothing on the PC.
Click to expand...
That's exactly what's happening.
 
When was last time you cleaned case filters and/or blew out PSU?
It's possible that dust/lint in grill mesh / filter mesh is restricting airflow causing fan to kick on to meet airflow demands. ;)
 
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