ConfigTemperature
Always is important configuring your CPU temperatures. You can use temperatures provided by the manufacturer and use this values in the configuration dialog.
Always you can use the sensors command to see the maximum temperatures detected for your CPU:
$ sensors
coretemp-isa-0000
Adapter: ISA adapter
Physical id 0: +61.0°C (high = +87.0°C, crit = +105.0°C)
Core 0: +60.0°C (high = +87.0°C, crit = +105.0°C)
Core 1: +61.0°C (high = +87.0°C, crit = +105.0°C)
Core 2: +56.0°C (high = +87.0°C, crit = +105.0°C)
Core 3: +57.0°C (high = +87.0°C, crit = +105.0°C)
You can use high and crit values.
In the most cases Intel and AMD are works without any problems.
Some new or old CPUs can have different ways to send information to KDE system monitor engine, then this plasmoid can have some problems to found propper values to display.
If your CPU temperatures can't shown, you can verify this temperatures with the plasmaengineexplorer application, provided in the most linux distros with KDE.
Using plasmaengineexplorer you can set the systemmonitor option for search your proper sensor CPU temperatures.
Find the lmsensors entry and send a screenshot or a list of lmsensors entry for you CPU to Issues page.
You can test this entries if you can set the lmsensor entry like that:
