These terms are related to processor temperature for desktop and mobile systems based on Intel® Processors. To allow optimal system operation and long-term reliability, the processor must not exceed the maximum case temperature specifications as defined by the applicable thermal profile.
Tcase is the temperature measurement using a thermocouple embedded in the center of the heat spreader. This initial measurement is done at the factory. Post-manufacturing, Tcase is calibrated by the BIOS, through a reading delivered by a diode between and below the cores.
Tjunction is synonymous with core temperatures, and calculated based on the output from the Digital Thermal Sensor (DTS) using the formula Tjunction = (Tjunction Max – DTS output). Tjunction Max (Tj Max) is also referred to as TCC Activation Temperature in certain processor datasheets.