IBM Intel Xeon E5-2637 49Y8125 User Manual

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Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families

Datasheet Volume One

A new feature in the processor is a software readable field in the 

TEMPERATURE_TARGET MSR 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.

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 via a combination of methods. The first method (Frequency/

SVID control) involves the processor adjusting its operating frequency (via the core 
ratio multiplier) and input voltage (via 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. 

operating within specifications. 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

C

 that exceeds the specified maximum temperature which 

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 Intel® Xeon® Processor E5-1600/E5-2600/
E5-4600 Product Families Thermal/Mechanical Design Guide 

for information on 

designing a 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.