Intel Q9300 Data Sheet - Page 83

On-Demand Mode

Page 83 highlights

Thermal Specifications and Design Considerations Figure 5-6. Thermal Monitor 2 Frequency and Voltage Ordering T TM2 f MAX f TM2 VID VID TM2 Temperature Frequency VID 5.2.3 PROCHOT# The PROCHOT# signal is asserted when a high temperature situation is detected, regardless of whether Thermal Monitor or Thermal Monitor 2 is enabled. It should be noted that the Thermal Monitor 2 TCC cannot be activated via the on demand mode. The Thermal Monitor TCC, however, can be activated through the use of the on demand mode. On-Demand Mode The processor provides an auxiliary mechanism that allows system software to force the processor to reduce its power consumption. This mechanism is referred to as "OnDemand" mode and is distinct from the Thermal Monitor feature. On-Demand mode is intended as a means to reduce system level power consumption. Systems using the processor must not rely on software usage of this mechanism to limit the processor temperature. If bit 4 of the ACPI P_CNT Control Register (located in the processor IA32_THERM_CONTROL MSR) is written to a '1', the processor will immediately reduce its power consumption via modulation (starting and stopping) of the internal core clock, independent of the processor temperature. When using On-Demand mode, the duty cycle of the clock modulation is programmable via bits 3:1 of the same ACPI P_CNT Control Register. In On-Demand mode, the duty cycle can be programmed from 12.5% on/87.5% off, to 87.5% on/12.5% off in 12.5% increments. On-Demand mode may be used in conjunction with the Thermal Monitor. If the system tries to enable On-Demand mode at the same time the TCC is engaged, the factory configured duty cycle of the TCC will override the duty cycle selected by the On-Demand mode. Datasheet 83

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Datasheet
83
Thermal Specifications and Design Considerations
The PROCHOT# signal is asserted when a high temperature situation is detected,
regardless of whether Thermal Monitor or Thermal Monitor 2 is enabled.
It should be noted that the Thermal Monitor 2 TCC cannot be activated via the on
demand mode. The Thermal Monitor TCC, however, can be activated through the use of
the on demand mode.
5.2.3
On-Demand Mode
The processor provides an auxiliary mechanism that allows system software to force
the processor to reduce its power consumption. This mechanism is referred to as “On-
Demand” mode and is distinct from the Thermal Monitor feature. On-Demand mode is
intended as a means to reduce system level power consumption. Systems using the
processor must not rely on software usage of this mechanism to limit the processor
temperature.
If bit 4 of the ACPI P_CNT Control Register (located in the processor
IA32_THERM_CONTROL MSR) is written to a '1', the processor will immediately reduce
its power consumption via modulation (starting and stopping) of the internal core clock,
independent of the processor temperature. When using On-Demand mode, the duty
cycle of the clock modulation is programmable via bits 3:1 of the same ACPI P_CNT
Control Register. In On-Demand mode, the duty cycle can be programmed from 12.5%
on/87.5% off, to 87.5% on/12.5% off in 12.5% increments. On-Demand mode may be
used in conjunction with the Thermal Monitor. If the system tries to enable On-Demand
mode at the same time the TCC is engaged, the factory configured duty cycle of the
TCC will override the duty cycle selected by the On-Demand mode.
Figure 5-6.
Thermal Monitor 2 Frequency and Voltage Ordering
VID
Frequency
Temperature
T
TM2
f
MAX
f
TM2
VID
VID
TM2
PROCHOT#