3.8 GHz P4-570 and E0 Stepping To End Intel's Performance Crisis

Overheat Protection Via Thermal Monitoring 2

Thermal Monitoring is the buzzword for Intel's protection mechanism that enforces thermal limits. It will throttle the core clock by skipping clock cycles to prevent the system from overheating and crashing.

Thermal Monitoring was first introduced with the Pentium 4 Willamette. If the processor temperature exceeds a threshold, the internal clock controller will simply stop the processor clock once in a while. This reduces thermal loss, while performance is clearly degraded as well.

Thermal Monitoring 2 is more intelligent, as the clock controller does not just skip clock cycles, but rather reduces the core clock using the PROCHOT signal. Should the CPU get too hot, the clock speed will be reduced to 2.8 GHz, while the older TM1 throttling function remains available in the case of an emergency. Since activating PROCHOT for protective reasons is done by the processor itself, this requires neither a BIOS update nor operating system changes.