Intel 2ND GENERATION CORE PROCESSOR FAMILY DESKTOP - THERMAL MECHANICAL S AND DESIGN GUIDELINES 01-2011, Specifications

Page: 53 / 134

Thermal/Mechanical Specifications and Design Guidelines 53
Thermal Specifications
6.2 Processor Thermal Features
6.2.1 Processor Temperature
A new feature in the processors is a software readable field in the
IA32_TEMPERATURE_TARGET register that contains the minimum temperature at
which the TCC will be activated and PROCHOT# will be asserted. The TCC activation
temperature is calibrated on a part-by-part basis and normal factory variation may
result in the actual TCC activation temperature being higher than the value listed in the
register. TCC activation temperatures may change based on processor stepping,
frequency or manufacturing efficiencies.
6.2.2 Adaptive Thermal Monitor
The Adaptive Thermal Monitor feature provides an enhanced method for controlling the
processor temperature when the processor silicon exceeds the Thermal Control Circuit
(TCC) activation temperature. Adaptive Thermal Monitor uses TCC activation to reduce
processor power via a combination of methods. The first method (Frequency/VID
control, similar to Thermal Monitor 2 (TM2) in previous generation processors) involves
the processor reducing its operating frequency (via the core ratio multiplier) and input
voltage (via the VID signals). This combination of lower frequency and VID results in a
reduction of the processor power consumption. The second method (clock modulation,
known as Thermal Monitor 1 or TM1 in previous generation processors) reduces power
consumption by modulating (starting and stopping) the internal processor core clocks.
The processor intelligently selects the appropriate TCC method to use on a dynamic
basis. BIOS is not required to select a specific method (as with previous-generation
processors supporting TM1 or TM2). The temperature at which Adaptive Thermal
Monitor activates the Thermal Control Circuit is factory calibrated and is not user
configurable. Snooping and interrupt processing are performed in the normal manner
while the TCC is active.
When the TCC activation temperature is reached, the processor will initiate TM2 in
attempt to reduce its temperature. If TM2 is unable to reduce the processor
temperature, then TM1 will be also be activated. TM1 and TM2 will work together
(clocks will be modulated at the lowest frequency ratio) to reduce power dissipation
and temperature.
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 so minor that it would be immeasurable. 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 in some cases may result in a T
CASE
that exceeds the specified maximum
temperature 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. Refer to the appropriate Thermal
Mechanical Design Guidelines for information on designing a compliant thermal
solution.
The Thermal Monitor does not require any additional hardware, software drivers, or
interrupt handling routines. The following sections provide more details on the different
TCC mechanisms used by the processor.