Intel BX80601920 Data Sheet - Page 76

Thermal Specifications 6.2 6.2.1 Note: 6.2.2 Processor Thermal Features Processor Temperature A new feature in the Intel Core™ i7-900 desktop processor Extreme Edition series and Intel Core™ i7-900 desktop processor series 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. There is no specified correlation between DTS temperatures and processor case temperatures; therefore it is not possible to use this feature to ensure the processor case temperature meets the Thermal Profile specifications. 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 using 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 (using the core ratio multiplier) and input voltage (using 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 (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 temperature cases may result in and may affect the laonTgC-AtSeErmtharet leiaxbcielietydsofththeespperocicfeiesdsomr.aIxnimadudmition, 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 processor Thermal and Mechanical Design Guide (see Section 1.2) 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 Intel Core™ i7-900 desktop processor Extreme Edition series and Intel Core™ i7-900 desktop processor series. 76 Datasheet