Asrock 870 Extreme 3 temperature sensors

any idea about that?

I doubt that sensor reading is correct or even is a true reading.

The sensor inputs and outputs available on the sensor chips used on mother boards are not all used by the board designers. There are very few standards regarding which sensor output belongs to which sensor reading. Plus there are many different kinds of sensor chips. To really know which sensor outputs are valid requires information from the board manufacture, which is rarely provided.

Hardware monitoring programs like the one you use provide the readings of what they consider to be the sensors most likely being used. It's just luck if they match the ones actually in use. Also, some sensor outputs require manipulation, meaning the raw sensor output must be multiplied or divided by a factor to give the correct reading.

Notice that the best it can do is label the values "Voltage #2", or "Temperature #3", which indicates they don't know what the reading is connected to, or if it is valid.

Temperature #2 is at best a reading that is not being adjusted appropriately, or simply a random, unused sensor output. That 115C value is 239F, nothing can actually be that temperature on your board.

A much better hardware monitoring program is HWiNFO, which can be found here for free:

http://www.hwinfo.com/download.php

It will also display some invalid readings, but it is one of the few programs that is tuned for different sensor chips and boards, as much as is possible.

You've told us virtually nothing about your PC, such as CPU, CPU cooler, PSU, any OC, PC case and cooling fans, etc.