Intel Core i7 Processor I7-940 AT80601000921AA User Manual

Datasheet 

77

The processor requires a thermal solution to maintain temperatures within its operating 
limits. Any attempt to operate the processor outside these operating limits may result 
in permanent damage to the processor and potentially other components within the 
system. Maintaining the proper thermal environment is key to reliable, long-term 
system operation.

A complete solution includes both component and system level thermal management 
features. Component level thermal solutions can include active or passive heatsinks 
attached to the processor integrated heat spreader (IHS).

This section provides data necessary for developing a complete thermal solution. For 
more information on designing a component level thermal solution, refer to the 
appropriate processor Thermal and Mechanical Design Guidelines (see 

The processor thermal specification uses the on-die Digital Thermal Sensor (DTS) value 
reported via the PECI interface for all processor temperature measurements. The DTS 
is a factory calibrated, analog to digital thermal sensor. As a result it will no longer be 
necessary to measure the processors case temperature. Consequently, there will be no 
need for a Thermal Profile specification defining the relationship between the 
processors T

CASE

 and power dissipation. 

Unless otherwise specified, the term “DTS” refers to the DTS value returned by from 

the PECI interface gettemp command.

A thermal solution that was verified compliant to the processor case temperature 

thermal profile at the customer defined boundary conditions is expected to be 

compliant with this update. No redesign of the thermal solution should be necessary. A 

fan speed control algorithms that was compliant to the previous thermal requirements 

is also expected to be compliant with this specification. The fan speed control algorithm 

can be updated to utilize the additional information to optimize acoustics.

To allow the optimal operation and long-term reliability of Intel processor-based 
systems, the processor thermal solution must deliver the specified thermal solution 
performance in response to the DTS sensor value. The thermal solution performance 
will be measured using a Thermal Test Vehicle (TTV). See 

the TTV thermal profile and 

 for the required thermal solution performance 

table when DTS values are greater than T

CONTROL

. Thermal solutions not designed to 

provide this level of thermal capability may affect the long-term reliability of the 
processor and system. When the DTS value is less than Tcontrol the thermal solution 
performance is not defined and the fans may be slowed down. This is unchanged from 
the prior specification. For more details on thermal solution design, refer to the 
appropriate processor Thermal and Mechanical Design Guidelines (see 

The processors implement a methodology for managing processor temperatures, which 
is intended to support acoustic noise reduction through fan speed control and to assure 
processor reliability. Selection of the appropriate fan speed is based on the relative 
temperature data reported by the processor’s Digital Temperature Sensor (DTS). The 
DTS can be read via the Platform Environment Control Interface (PECI) as described in