The reasons are,
1. The purpose of the CPU temperature shown in BIOS setup menu is for thermal control use. It is a
reference value for CPU to manage the fan speed to let CPU work efficient and effective. So the
reference temperature for the CPU may be not mapped with actual.
2. For avoiding misunderstanding and recommended by AMD, when the CPU temperature was read
lower than expected, it might display 40 degrees to get close to real temperature. For example, if it is
30 degrees, it will display at 40 degrees in CMOS setup till reading temperature over 40 degrees.