And this wasnt the only mechanism. Before THERMTRIP# triggers there is also diode based temp sensor embedded in later CPUs (THERMDP, THERMDN) Mobo designer can use to trigger either STPCLK# directly
or southbridge THRM# pin which in turn actuates build-in ACPI interface with programmable Thermal Duty Cycle CPU throttling (THRM_DTY using STPCLK#) in 12.5% steps (6% steps in later revisions of ACPI interface).
AMD didnt have thermal sensor on CPU Die in early CPUs, they had an app note requiring Mobo makers integrate external sensor under socket. No one bothered, not even good brands like Siemens, and we got famous Toms Hardware article with video of AMD CPU burning into a crisp after taking off radiator on Siemens mobo.
And this wasnt the only mechanism. Before THERMTRIP# triggers there is also diode based temp sensor embedded in later CPUs (THERMDP, THERMDN) Mobo designer can use to trigger either STPCLK# directly
Pentium® III Processor Active Thermal Management Techniques http://notes-application.abcelectronique.com/027/27-46150.pd...
or southbridge THRM# pin which in turn actuates build-in ACPI interface with programmable Thermal Duty Cycle CPU throttling (THRM_DTY using STPCLK#) in 12.5% steps (6% steps in later revisions of ACPI interface).
82371AB PCI-TO-ISA / IDE XCELERATOR (PIIX4) datasheet https://theretroweb.com/chip/documentation/29056201-64f6fb6f...
AMD didnt have thermal sensor on CPU Die in early CPUs, they had an app note requiring Mobo makers integrate external sensor under socket. No one bothered, not even good brands like Siemens, and we got famous Toms Hardware article with video of AMD CPU burning into a crisp after taking off radiator on Siemens mobo.