Hi everyone

I have been trying for the last few days to monitor the temperature of my computer with lm-sensors and sensors applet.
Here is what I get using the sensor command:

acpitz-virtual-0
Adapter: Virtual device
temp1: +80.0°C (crit = +86.0°C)

coretemp-isa-0000
Adapter: ISA adapter
Core 0: +25.0°C (crit = +90.0°C)

Notice the discrepancy between the two temperatures. The acpi temperature reading seems to freeze at 80°C after 15mn of web browsing. From the moment I turn on the computer to that point, the acpi temp stays within the 40-55°C range, then a second later it get to 80°c and the acpi temp reading freezes. However, the coretemp remains in the 25-40°c range even hours later, and does not freeze.

So, which is the right temperature? I wonder if there is a problem with the sensors or if i am simply overheating my computer ?