Thermal Specifications

6.4.1Intel® Turbo Boost Technology Power Control and Reporting

When operating in the turbo mode, the processor will monitor its own power and adjust the turbo frequency to maintain the average power within limits over a thermally significant time period. The package, processor core, and graphic core powers are estimated using architectural counters and do not rely on any input from the platform.

The behavior of turbo is dictated by the following controls that are accessible using MSR, MMIO, or PECI interfaces:

•POWER_LIMIT_1: TURBO_POWER_LIMIT, MSR 610h, bits 14:0. This value sets the exponentially weighted moving average power limit over a long time period. This is normally aligned to the TDP of the part and steady-state cooling capability of the thermal solution. This limit may be set lower than TDP, real-time, for specific needs, such as responding to a thermal event. If set lower than TDP, the processor may not be able to honor this limit for all workloads since this control only applies in the turbo frequency range; a very high powered application may exceed POWER_LIMIT_1, even at non-turbo frequencies. The default value is the TDP for the SKU.

•POWER_LIMIT_1_TIME: TURBO _POWER_LIMIT, MSR 610h, bits 23:17. This value is a time parameter that adjusts the algorithm behavior. The exponentially weighted moving average turbo algorithm will use this parameter to maintain time averaged power at or below POWER_LIMIT_1.

•POWER_LIMIT_2: TURBO_POWER_LIMIT, MSR 610h, bits 46:32. This value establishes the upper power limit of turbo operation above TDP, primarily for platform power supply considerations. Power may exceed this limit for up to 10 mS. The default for this limit is 1.25 x TDP.

The following considerations and limitations apply to the power monitoring feature:

•Calibration applies to the processor family and is not conducted on a part-by-part basis. Therefore, some difference between actual and reported power may be observed.

•Power monitoring is calibrated with a variety of common, realistic workloads near Tj_max. Workloads with power characteristic markedly different from those used during the calibration process or lower temperatures may result in increased differences between actual and estimated power.

•In the event an uncharacterized workload or power “virus” application were to result in exceeding programmed power limits, the processor Thermal Control Circuitry (TCC) will protect the processor when properly enabled. Adaptive Thermal Monitor must be enabled for the processor to remain within specification.

Illustration of Intel Turbo Boost Technology power control is shown in the following sections and figures. Multiple controls operate simultaneously allowing for customization for multiple system thermal and power limitations. These controls allow for turbo optimizations within system constraints.

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Thermal/Mechanical Specifications and Design Guidelines