Data Sheet

Datasheet, Volume 1 of 2 93
Thermal Management
be subtracted from the Tj
MAX
value and used as a new max temperature set point for
Adaptive Thermal Monitoring. This will have the same behavior as in prior products to
have TCC activation and Adaptive Thermal Monitor to occur at this lower target silicon
temperature.
If enabled, the offset should be set lower than any other passive protection such as
ACPI _PSV trip points
TCC Activation Offset with Tau
To manage the processor with the EWMA (Exponential Weighted Moving Average) of
temperature, an offset (degrees Celsius) is written to the TEMPERATURE_TARGET
(0x1A2) MSR, bits [29:24], and the time window (Tau) is written to the
TEMPERATURE_TARGET (0x1A2) MSR [6:0]. The Offset value will be subtracted from
the value found in bits [23:16] and be the temperature.
The processor will manage to this average temperature by adjusting the frequency of
the various domains. The instantaneous Tj can briefly exceed the average temperature.
The magnitude and duration of the overshoot is managed by the time window value
(Tau).
This averaged temperature thermal management mechanism is in addition, and not
instead of Tj
MAX
thermal management. That is, whether the TCC activation offset is 0 or
not, TCC Activation will occur at Tj
MAX
.
5.1.5.1.2 Frequency / Voltage Control
Upon Adaptive Thermal Monitor activation, the processor attempts to dynamically
reduce processor temperature by lowering the frequency and voltage operating point.
The operating points are automatically calculated by the processor IA core itself and do
not require the BIOS to program them as with previous generations of Intel processors.
The processor IA core will scale the operating points such that:
• The voltage will be optimized according to the temperature, the processor IA core
bus ratio and number of processor IA cores in deep C-states.
• The processor IA core power and temperature are reduced while minimizing
performance degradation.
Once the temperature has dropped below the trigger temperature, the operating
frequency and voltage will transition back to the normal system operating point.
Once a target frequency/bus ratio is resolved, the processor IA core will transition to
the new target automatically.
• On an upward operating point transition the voltage transition precedes the
frequency transition.
• On a downward transition the frequency transition precedes the voltage transition.
• The processor continues to execute instructions. However, the processor will halt
instruction execution for frequency transitions.
If a processor load-based Enhanced Intel
®
SpeedStep
®
Technology/P-state transition
(through MSR write) is initiated while the Adaptive Thermal Monitor is active, there are
two possible outcomes:
• If the P-state target frequency is higher than the processor IA core optimized
target frequency, the P-state transition will be deferred until the thermal event has
been completed.