Question Fans running full speed

May 18, 2020
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I have recently replaced my sons motherboard in his pc and all seemed well. However his cpu and system fans are running full speed. I have tried going into the bios but there is no power tab and i cannot see any way to adjust the fan speeds.
 
May 18, 2020
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I searched hi and low and found the following on Amazon
Jarhit H81 LGA 1150 Motherboard Socket LGA1150 Micro-ATX Desktop image
 
May 18, 2020
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I opened the bios but could mot find any ref to fan speed anywhere. The websites and videos all show the power tab and smart fan options but not on my bios which if i am reading correctly is American Megatrends
 

justquant

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Oct 1, 2018
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The system fan is 3 pin both connect to mobo
I opened the bios but could mot find any ref to fan speed anywhere. The websites and videos all show the power tab and smart fan options but not on my bios which if i am reading correctly is American Megatrends
If the fans are 3-pin they lack PWM and so they do not ramp up with heat. Since system fan headers are usually at 12V, they run at full blast all the time unless there is a BIOS option to adjust voltage to 3V, 5V or 12V.
 

justquant

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Oct 1, 2018
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I only notice a CPU_FAN header on that board, no case (system) fan headers to be found. Have you connected the fans directly to the PSU, or did you use a fan splitter on the CPU_FAN header?

EDIT: Nevermind, I see the SYS_FAN header. That is only a 3-pin header, and looking at the motherboard and what you said earlier, it seems it still uses BIOS instead of UEFI, and so you may not be able to change the headers' voltage, meaning it'll probably have to run at full speed all the time.
 
May 18, 2020
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The case fan is connected to a 3 pin socket directly opposite the audio jack and next to the main power cable connection on the motherboard
 

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