(1) Tjunction Max differs according to Stepping.
(2) Tjunction Max 85c (or 100c) is used by software utilities to determine Tjunction.
(3) Tcase is the CPU temp reported in BIOS.
(4) Stepping (not Cache) determines Tcase Max. Most are 60c. Some L2 and G0 Steppings are 72c.
(5) The single on-die CPU Case Thermal Diode is independent of the Cores, only measures Tcase, and does not trigger TCC.
Although Tcase typically scales ~ 15c (+ / - 3c) below Tjunction, Tcase and Tjunction are not alwas linear with respect to one another due to variables such as Vcore, clock speed and work load. The Digital Thermal Sensors (DTS) within the hot spot of each Core measure Tjunction, and are used to individually trigger TCC (TM1 and TM2), PROCTHERM, and THERMTRIP for each core. When Tjunction Max is reached and shutdown (THERMTRIP) occurs, Tcase Max has probably been exceeded, therefore, Tcase has no effect on triggering TCC.
For example, the E6400 L2 Stepping is Tcase Max 61c / Tjunction Max 100c, which makes absolutely no sense. At a throttle threshold of Tjunction 95c, even with an extremely high Tcase to Tjunction Delta of 20c, Tcase would still be 75c, which would far exceed Tcase Max by 14c. Permanent processor damage may occur when Tcase is sustained above 67c.
More typically, the E6600 B2 Stepping is Tcase Max 60c / Tjunction Max 85c, so at a throttle threshold of Tjunction 80c, with a Tcase to Tjunction Delta of 18c, Tcase would be a more reasonable 62c, which would only exceed Tcase Max by 2c, and not cause permanent processor damage. As you can see, when compared, some of Intels specs leave something to be desired.
Even if more recent C2D's (E6X50 Stepping G0 with Tcase Max 72c / Tjunction Max 100c) are designed with greater thermal tolerances to better cope with variables such as temperature fluctuations in high ambient environments, it is not recommended to continually operate processors, overclocked or stock, above Tcase 60c / Tjunction 75c, for reasons of stability, as well as longevity.
Hope this helps,
Comp