Why is my motherboard temperature a constant arbitrary number?

checked with Piriform Speccy.

checked with open hardware monitor

checked with hardware sensor monitor(this one shows different statistics)

Solution 1:

Your motherboard is not at 123'c. The application is reading a sensor that does not exist, or is reading data in a format it doesn't understand properly.

Not all motherboards have the same number of sensors, and not all sensor chips have all inputs connected. Sensors that are not connected will often give imaginary readings, whether that be zero, 123'c, 65535'c or any other temperature. It is also not unknown for negative temperatures, e.g. -127'c to be reported as well for unconnected sensors. The actual value used as "null" or "no reading" is specific to the driver and sensor chip in question.

Try to update to the latest drivers in order to fix sensor detection issues: Intel NUC Kit D54250WYK

Solution 2:

Whether or not the 123 degrees Celsius number is real, the 15.79 volts for the +12V power bus is rather concerning. I would recommend you go back into your bios and see if it agrees that the voltage is 15. If so, power off your computer at once, as this may indicate a faulty power supply or motherboard. If your power supply is really so far off, it's at least possible that the 123 degrees reading is real.