Processors
Intel® Pentium® III Processor
Thermal management for Intel® Pentium® III processors

Introduction
Systems using Intel® Pentium® III processors all require thermal management. It is assumed that the reader has a general knowledge of and experience with PC operation, integration, and thermal management. Integrators who follow the recommendations presented here can provide their customers with more reliable PCs and will see fewer customers returning with problems. (The term "boxed Pentium III processors" refers to processors packaged for use by system integrators.)

Allowing processors to operate at temperatures beyond their maximum specified operating temperature will lessen the lifetime of the processor and can cause unreliable operation. It is critical when building quality systems using the boxed Pentium III processor to carefully consider the thermal management of the system and verify the system design with thermal testing. This document details specific thermal requirements of the boxed Pentium III processor. System integrators using the boxed Pentium III processor should become familiar with this document as well as the two listed below.

Related Documents
The following documents describe thermal testing, thermal management, and proper integration of a boxed processor in order to improve system quality and reliability. Use these documents in conjunction with the information on this page.

  1. System Thermal Management for Boxed Intel Processor-Based Desktop PCs:
    This document details general recommendations for improving system thermal management in desktop systems that use boxed Intel processors.

  2. Thermal Testing with Thermocouples and Thermal Meters on Intel Boxed Processor-Based Desktop PCs:
    This document describes the use of thermocouples and thermal meters for testing Intel boxed processor-based desktop systems. Thermocouples can be used to test temperatures critical to the proper operation of boxed processors. The document also discusses what software to use while doing thermal testing.

Thermal Management
The term "thermal management" refers to two major elements: a heatsink properly mounted to the processor, and effective airflow through the system chassis. The ultimate goal of thermal management is to keep the processor at or below its maximum operating temperature.

Proper thermal management is achieved when heat is transferred from the processor to the system air, which is then vented out of the system. Boxed Pentium III processors are shipped with an attached high-quality fan heatsink, which can effectively transfer processor heat to the system air. It is the responsibility of the system integrator to ensure adequate system airflow.

Fan Heatsink
The fan heatsink that ships with the boxed Pentium III processor has already been securely attached to the processor. Thermal interface material (already applied) provides effective heat transfer from the processor to the fan heatsink. The fan cable provides power to the fan by connecting to a motherboard-mounted power header and also allows the fan to provide fan speed information to the motherboard. (Only motherboards with hardware monitoring circuitry can use the fan speed signal.)

The fan is a high-quality ball bearing fan that provides a good local air stream. This local air stream transfers heat from the heatsink to the air inside the system. However, moving heat to the system air is only half the task. Sufficient system airflow is also needed in order to exhaust the air. Without a steady stream of air through the system, the fan heatsink will re-circulate warm air that may not cool the processor adequately.

Chassis Recommendations
Intel recommends the use of ATX and microATX form factor motherboards and chassis for the boxed Pentium III processor. The ATX and microATX form factors simplify assembly and upgrading of PCs, while improving the consistency of airflow to the processor. For more information, see System Thermal Management for Boxed Intel Processor-Based Desktop PCs.

Pentium III Processor Thermal Recommendations
Table 1 also shows the power dissipation for boxed Pentium III processors. Processors that dissipate more power will also generate more heat. Use the thermal test methodology described in Thermal Testing with Thermocouples and Thermal Meters on Intel Boxed Processor-Based Desktop PCs to test thermal management of boxed Pentium III processor-based systems. When building 242-contact slot connector systems that will feature boxed Pentium III processors, testing should be performed using the 600-MHz or a 600B-MHz processor because it dissipates the most power. When building 370-pin socket systems that will feature boxed Pentium III processors, testing should be performed using the 550E-MHz processor because it dissipates the most power.

To determine the temperature of the processor core per the specification, use the thermal methodology described in AP-905 Pentium III Processor Thermal Design Guidelines (order #245087). The process this document describes involves purchasing an evaluation kit and using the processor's thermal diode.

Table 1. Pentium® III Processor Thermal Specifications1


Processor Frequency
Form Factor Temperatures
Total Max Processor Power

Max Core (TJ)

Max Plate (TCASE)

Fan Inlet (TA)3

Heatsink Base (THS)5
1.40 GHz-
S7
FC-PGA2 N/A 69°C 45°C N/A5 31.2 W
1.26 GHz-
S7
FC-PGA2 N/A 69°C 45°C N/A5 29.5 W
1.20 GHz7 FC-PGA2 N/A 69°C 45°C N/A5 29.9 W
1.13 GHz-S7 FC-PGA2 N/A 69°C 45°C N/A5 27.9 W
1.13 GHz7 FC-PGA2 N/A 69°C 45°C N/A5 29.1 W
1 GHz FC-PGA2 N/A N/A 45°C N/A5 29.0 W
1 GHz FC-PGA 70°C2 N/A 45°C N/A5 30.0 W
1 GHz FC-PGA 70°C2 N/A 45°C N/A5 26.1 W
9335 MHz FC-PGA 77°C2 N/A 45°C N/A5 28.3 W
933 MHz S.E.C.C.2 75°C2 N/A 45°C N/A5 25.5 W
933 MHz FC-PGA 75°C2 N/A 45°C N/A5 24.5 W
900 MHz FC-PGA 75°C2 N/A 45°C N/A5 23.2 W
8665 MHz FC-PGA 80°C2 N/A 45°C N/A5 27.1 W
866 MHz S.E.C.C.2 80°C2 N/A 45°C N/A5 22.9 W
866 MHz FC-PGA 80°C2 N/A 45°C N/A5 22.9 W
850 MHz S.E.C.C.2 80°C2 N/A 45°C N/A5 22.5 W
850 MHz FC-PGA 80°C2 N/A 45°C N/A5 22.5 W
800EB MHz S.E.C.C.2 80°C2 N/A 45°C N/A5 20.8 W
800EB MHz FC-PGA 80°C2 N/A 45°C N/A5 20.8 W
800 MHz S.E.C.C.2 80°C2 N/A 45°C N/A5 20.8 W
800 MHz FC-PGA 80°C2 N/A 45°C N/A5 20.8 W
750 MHz S.E.C.C.2 80°C2 N/A 45°C N/A5 19.5 W
750 MHz FC-PGA 80°C2 N/A 45°C N/A5 19.5 W
733 MHz S.E.C.C.2 80°C2 N/A 47°C N/A5 19.1 W
733 MHz FC-PGA 80°C2 N/A 47°C N/A5 19.1 W
700 MHz S.E.C.C.2 80°C2 N/A 47°C N/A5 18.3 W
700 MHz FC-PGA 80°C2 N/A 47°C N/A5 18.3 W
667 MHz S.E.C.C.2 82°C2 N/A 50°C N/A5 17.5 W
667 MHz FC-PGA 82°C2 N/A 50°C N/A5 17.5 W
650 MHz S.E.C.C.2 82°C2 N/A 53°C N/A5 17.0 W
650 MHz FC-PGA 82°C2 N/A 53°C N/A5 17.0 W
600EB MHz S.E.C.C.2 82°C2 N/A 48°C N/A5 15.8 W
600EB MHz FC-PGA 82°C2 N/A 48°C N/A5 15.8 W
600E MHz S.E.C.C.2 82°C2 N/A 48°C N/A5 15.8 W
600E MHz FC-PGA 82°C2 N/A 48°C N/A5 15.8 W
600B MHz S.E.C.C.2 85°C2 N/A 45°C 60°C 34.5 W
600 MHz S.E.C.C.2 85°C2 N/A 45°C 60°C 34.5 W
550E MHz S.E.C.C.2 85°C2 N/A 50°C N/A5 14.5 W
550E MHz FC-PGA 85°C2 N/A 50°C N/A5 14.5 W
550 MHz S.E.C.C.2 80°C2 N/A 45°C 60°C 30.8 W
533EB MHz S.E.C.C.2 82°C2 N/A 50°C N/A5 14.0 W
533EB MHz FC-PGA 82°C2 N/A 50°C N/A5 14.0 W
533B MHz S.E.C.C.2 90°C2 N/A 47°C 61°C 29.7 W
500E MHz FC-PGA 85°C2 N/A 53°C N/A4 13.2 W
500 MHz S.E.C.C.2 90°C2 N/A 50°C 62°C 28.0 W
450 MHz S.E.C.C.2 90°C2 N/A 53°C 65°C 25.3 W
  1. The maximum operating temperature and maximum power specification are specifications from the processor datasheet. The recommended fan inlet temperature (TAM) and the recommended heatsink base temperature (THS) are not specification, see note 3 and 4. For more information on Pentium III processor specifications, see the Pentium III Processor Datasheet.

  2. The junction temperature (TJ) can be determined using the thermal diode in the processor core. For more information, see the AP-905 Pentium III Processor Thermal Design Guidelines (order # 245087).

  3. The recommended fan inlet temperature (TA) should be measured at the inlet of the fan heatsink on the boxed processor (see Figure 1 and 3). This is a maximum value and a recommendation only, not a specification.

  4. The recommended heatsink base temperature (THS) should be measured at the center of the top of the heatsink base near the processor markings (see Figure 1). This is a maximum value and a recommendation only, not a specification.

  5. This method of validation is not appropriate for processors in the socketed form factor.

  6. This part has a Vcc of 1.75 volts.

  7. This processor is manufactured on the 0.13 micron process.

A simple evaluation of the temperature of the heatsink base can provide confidence in the system's thermal management. For boxed Pentium III processors in the S.E.C.C.2 form factor, the testing point is at the center of the heatsink base on the top of the processor near to the processor marking area (see Figure 1). The document titled Thermal Testing with Thermocouples and Thermal Meters on Intel Boxed Processor-Based Desktop PCs describes how to determine the temperature of this location while running a high power application. Using this evaluation, it is possible to determine if a system has sufficient thermal management for the boxed processor. A more general evaluation can be done by testing the temperature of the air entering the fan inlet. Table 1 contains the recommended temperature that the heatsink base test point or the air inlet temperature should remain below during the thermal evaluation of a system.

Figure 1. Temperature Test Locations for Boxed Pentium III Processors in the S.E.C.C.2 Form Factor
Temperature Test Locations for Boxed Pentium® III Processors in the S.E.C.C.2 Form Factor

For boxed Pentium III processors in the FC-PGA package, the testing point is 0.3 inches above the center of the fan inlet. (see Figure 2).

Figure 2. FC-PGA Boxed Pentium® III Processors Temperature Test
Locations

Figure 2. FC-PGA Boxed Pentium® III Processors Temperature Test Locations



Fahrenheit to Celsius Conversion Chart
° F ° C ° F ° C ° F ° C ° F ° C
59.0 15 89.6 32 120.2 49 150.8 66
60.8 16 91.4 33 122.0 50 152.6 67
62.6 17 93.2 34 123.8 51 154.4 68
64.4 18 95.0 35 125.6 52 156.2 69
66.2 19 96.8
36 127.4 53 158.0 70
68.0 20 98.6 37 129.2 54 159.8 71
69.8 21 100.4 38 131.0 55 161.6 72
71.6 22 102.2 39 132.8 56 163.4 73
73.4 23 104.0 40 134.6 57 165.2 74
75.2 24 105.8 41 136.4 58 167.0 75
77.0 25 107.6 42 138.2 59 168.8 76
78.8 26 109.4 43 140.0
60 170.6 77
80.6 27 111.2 44 141.8 61 172.4 78
82.4 28 113.0 45 143.6 62 174.2 79
84.2 29 114.8 46 145.4 63 176.0 80
86.0 30 116.6 47 147.2 64    
87.8 31 118.4 48 149.0 65    


Typical office room temperature.
Typical maximum operating room temperature for a system in an air-conditioned environment.
Typical maximum operating room temperature for a system in a non-air-conditioned environment.

This applies to:

Intel® Pentium® III Processor



Solution ID: CS-007589
Last Modified: 02-Dec-2011
Date Created: 10-Dec-2003
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