Improved Thermal Monitor Mode

The Thermal Monitor mode (see “The Thermal Monitoring Facilities” on page 1340) has been enhanced (and is referred to as Thermal Monitor 2). Rather than using the internal Stop Clock signal's duty cycle to control the processor's internal temperature, it automatically controls the processor's BCLK-to-processor clock ratio and core operating voltage. This is referred to as Intel® Mobile Voltage Positioning (IMVP):

• When the on-die thermal sensor indicates that the die temperature is too high, the processor can automatically perform a transition to a lower frequency/voltage specified in a software programmable MSR (not documented in the public domain).

• The processor waits for a fixed time period. If the die temperature is down to acceptable levels, a transition to the previous frequency/voltage point occurs.

• An interrupt can be generated for the up and down transitions, enabling better system-level thermal management.