Intel Pentium M 770 RH80536GE0462M Data Sheet

Datasheet

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The Intel Thermal Monitor helps control the processor temperature by activating the 

TCC (Thermal Control Circuit) when the processor silicon reaches its maximum 

operating temperature. The temperature at which the Intel Thermal Monitor activates 

the TCC is not user configurable. Bus traffic is snooped in the normal manner, and 

interrupt requests are latched (and serviced during the time that the clocks are on) 

while the TCC is active.

With a properly designed and characterized thermal solution, it is anticipated that the 

TCC would only be activated for very short periods of time when running the most 

power intensive applications. The processor performance impact due to these brief 

periods of TCC activation is expected to be minor and hence not detectable. An under-

designed thermal solution that is not able to prevent excessive activation of the TCC in 

the anticipated ambient environment may cause a noticeable performance loss, and 

may affect the long-term reliability of the processor. In addition, a thermal solution that 

is significantly under designed may not be capable of cooling the processor even when 

the TCC is active continuously.

The Intel Thermal Monitor controls the processor temperature by modulating (starting 

and stopping) the processor core clocks or by initiating an Enhanced Intel SpeedStep 

Technology transition when the processor silicon reaches its maximum operating 

temperature. The Intel Thermal Monitor uses two modes to activate the TCC: 

Automatic mode and on-demand mode. If both modes are activated, Automatic mode 

takes precedence. 

The Intel Thermal Monitor automatic mode must be enabled through BIOS for the 

processor to be operating within specifications. 

There are two automatic modes called Intel Thermal Monitor 1 (TM1) and Intel Thermal 

Monitor 2 (TM2). These modes are selected by writing values to the Model Specific 

Registers (MSRs) of the processor. After Automatic mode is enabled, the TCC will 

activate only when the internal die temperature reaches the maximum allowed value 

for operation. 

Likewise, when Intel Thermal Monitor 2 is enabled, and a high temperature situation 

exists, the processor will perform an Enhanced Intel SpeedStep technology transition to 

a lower operating point. When the processor temperature drops below the critical level, 

the processor will make an Enhanced Intel SpeedStep technology transition to the last 

requested operating point. 

TM1 and TM2 can co-exist within the processor. If both TM1 and TM2 bits are enabled in 

the auto-throttle MSR, TM2 will take precedence over TM1. However, if TM2 is not 

sufficient to cool the processor below the maximum operating temperature then TM1 

will also activate to help cool down the processor. Intel recommends Thermal Monitor 1 

and Thermal Monitor 2 be enabled on the Intel Pentium Dual-Core processor. 

If a processor load based Enhanced Intel SpeedStep technology transition (through 

MSR write) is initiated when an Intel Thermal Monitor 2 period is active, there are two 

possible results:

1. If the processor load based Enhanced Intel SpeedStep technology transition target 

frequency is higher than the Intel Thermal Monitor 2 transition based target 

frequency, the processor load-based transition will be deferred until the Intel 

Thermal Monitor 2 event has been completed.

2. If the processor load-based Enhanced Intel SpeedStep technology transition target 

frequency is lower than the Intel Thermal Monitor 2 transition based target 

frequency, the processor will transition to the processor load-based Enhanced Intel 

SpeedStep technology target frequency point.