wb, Re: TDP (the Thermal Design Point) is somewhat empirical, rather than an exact specification. In order to derive it, you have to test how real applications dissipate power. The end result is that if a system designer constructs a cooling solution that can dissipate that many watts, while keeping case temperature (also called junction temperature, or Tj)? below a stated specification (usually in the range of 50-100C degrees).>
Heat originates within the Cores, and is hottest where the dual Tjunction sensors are located. Heat is then dissipated throughout the CPU die to the socket and motherboard, and to the Integrated Heat Spreader, where the single Tcase sensor is located between the Cores, and the temperature is ~ 15c cooler. Heat is then transferred to the CPU cooler, and finally to air inside the computer case, where all 3 C2D temperatures are determined by computer case cooling efficiency, Ambient temperature, and Vcore. At 100% Load, Tjunction is ~ 15c higher than Tcase, and Tcase is always higher than Ambient.
tomshardware.com That's for Intel C2Ds.
So Intel defines Tcase as the temperature of the heat spreader at a point not local to a die...
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