PC case fans constantly turning on and off.

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sunfire0816

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I built a PC roughly 3 months ago. Everything was working perfectly fine. Then about 2 weeks ago, my case fans started turning on, ramping up to 100%, and then shutting off. They used to run at low RPMs until I put a heavier load on the computer, then they would increase speed. Now they turn on and turn off randomly. How do I fix this issue?
 

vger

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Hello

Could be your psu.. Just how long will the pc stay on? Assuming that is what you meant when shutting off.
 

sunfire0816

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Hello

Could be your psu.. Just how long will the pc stay on? Assuming that is what you meant when shutting off.
It’s not the PC, it’s only the case fans that are turning on and off. The PC works just fine aside from the 4 case fans.
 

sunfire0816

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Nope, they just turn off, and then will start right back up again. And keep repeating that. If I turn the PC off and turn it back on, the fans start all over again of turning on and turning off, and turning on and turning off
 

sunfire0816

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So, I found out, the two headers I had my fans plugged into would only receive power when the CPU usage went up, regardless of how much. Then once the CPU usage dropped back down, those headers would no longer receive power causing the fans to shut off.
 

vger

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So if this setup is what you want,it looks like it is working like it is suppose to.. Or find a different power port on your mobo..( like an auxiliary power port)
 

gus

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There is probably some fan settings that can be adjusted in the bios to customize this behaviour?
 
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