Intel 640 User Guide - Page 31
Thermal Management Logic and, Thermal Monitor Feature
UPC - 683728178901
View all Intel 640 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 31 highlights
Thermal Management Logic and Thermal Monitor Feature R 4 4.1 4.2 Thermal Management Logic and Thermal Monitor Feature Processor Power Dissipation An increase in processor operating frequency not only increases system performance, but also increases the processor power dissipation. The relationship between frequency and power is generalized in the following equation: P = CV2F (where P = power, C = capacitance, V = voltage, F = frequency). From this equation, it is evident that power increases linearly with frequency and with the square of voltage. In the absence of power saving technologies, ever increasing frequencies will result in processors with power dissipations in the hundreds of watts. Fortunately, there are numerous ways to reduce the power consumption of a processor, and Intel is aggressively pursuing low power design techniques. For example, decreasing the operating voltage, reducing unnecessary transistor activity, and using more power efficient circuits can significantly reduce processor power consumption. An on-die thermal management feature called Thermal Monitor is available on the Pentium 4 processor in the 775-land LGA package. It provides a thermal management approach to support the continued increases in processor frequency and performance. By using a highly accurate ondie temperature sensing circuit and a fast acting Thermal Control Circuit (TCC), the processor can rapidly initiate thermal management control. The Thermal Monitor can reduce cooling solution cost, by allowing thermal designs to target TDP. Thermal Monitor Implementation On the Pentium 4 processor in the 775-land LGA package, the Thermal Monitor is integrated into the processor silicon includes: • A bi-directional signal (PROCHOT#) that indicates if the processor has exceeded its maximum temperature or can be asserted externally to activate the Thermal Control Circuit (TCC). • A Thermal Control Circuit that will attempt to reduce processor temperature by rapidly reducing power consumption when the on-die temperature sensor indicates that it has exceeded the maximum operating point. • Registers to determine the processor thermal status. Thermal/Mechanical Design Guide 31