Motherboard temperature sensor failure causing high cpu temperatures.

[Itisme754]

Hi,
my PC crashed several times and I noticed that the CPU was very hot so I installed a sensors logging software to figure out what's going on.
Turns out a motherboard sensor stops showing any data, causing the cpu fan to slow down and eventually to stop. The CPU temperature then goes up and crashes my computer.

So the problem is the motherboard, right?

 

[martin4oto6]

Can you physically see or hear the fan slowing down?

 

[scuzzycard]

Your CPU's fan speed should vary based on the CPU temperature reported by the CPU's internal sensor. Do you have your CPU fan plugged into the correct header?

 

[Itisme754]

Can you physically see or hear the fan slowing down?

Yes, I saw it slowing down and eventually stopping.

Your CPU's fan speed should vary based on the CPU temperature reported by the CPU's internal sensor. Do you have your CPU fan plugged into the correct header?

Yes, I even tried another cpu fan just to make sure and same thing happened.

 

[Itisme754]

Any thoughts?

 

[scuzzycard]

You're correct about the motherboard being the problem. If it's still under warranty, by all means RMA it. If not, or you don't want the hassle, you have some options. First, I would see if you can set the fan manually to a fixed speed in the BIOS. If that works, the only downside will be extra noise at idle. If not, you have more options. I'm assuming the fan is 4-pin PWM? You can swap in a 3-pin fan and use an adapter to power it from a SATA power connect or 4-pin molex. Even better, you can get a fan controller. The more elaborate ones come with OLED touch screens and their own temperature sensors and will increase the speed of the fan as the CPU temperature rises according to your settings.