Table of Contents
Advertisement
6.2
Processor Core Thermal Features
6.2.1
Processor Temperature
A feature in the processor 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_N 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 reaches its maximum operating
temperature. Adaptive Thermal Monitor uses Thermal Control Circuit (TCC) activation
to reduce processor power using a combination of methods. The first method
(Frequency/SVID control) involves the processor adjusting its operating frequency
(using the core ratio multiplier) and input voltage (using the SVID signals). This
combination of reduced frequency and voltage results in a reduction to the processor
power consumption. The second method (clock modulation) 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 Adaptive Thermal Monitor feature must be enabled for the processor to be
operating within specifications. The temperature at which Adaptive Thermal
Monitor activates the Thermal Control Circuit is not user configurable and is not
software visible. Snooping and interrupt processing are performed in the normal
manner while the TCC is active.
With a properly designed and characterized thermal solution, it is anticipated that the
TCC would 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
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
compliant thermal solution.
The duty cycle for the TCC, when activated by the Thermal Monitor, is factory
configured and cannot be modified. The Thermal Monitor does not require any
additional hardware, software drivers, or interrupt handling routines.
48
that exceeds the specified maximum temperature which
C
Chapter 8
Thermal/Mechanical Specifications and Design Guide
Thermal Management Specifications
for information on designing a
Advertisement
Table of Contents
