Processors
Intel® Pentium® III Xeon® Processor
Integration notes

Updated November 2001

This overview is for professional system integrators building workstations and mid range and higher servers with Intel® Pentium® III Xeon™ processors and industry-accepted motherboards, chassis, and peripherals. For information on the Intel® Pentium II Xeon™ processor, see the Integration Overview for Intel Pentium II Xeon Processor-Based Systems.

Pentium® III Xeon™ Processor Features
The Pentium III Xeon processor is part of the new Intel Inside® microprocessor family designed exclusively for today's powerful servers and workstations. Building on the architecture of the Pentium II Xeon processor, the Pentium III Xeon processor adds the superior performance of Internet Streaming SIMD Extensions.


Powering Servers and Workstations to New Levels of Performance
Internet Streaming SIMD Extensions includes 70 new instructions that accelerate the performance of today's performance-demanding workstation applications, including CAD, digital content creation, 3D modeling, and real-time physics simulation. Servers using the Pentium III Xeon processor deliver outstanding performance for net connectivity, database processing, and file compression/decompression. The Pentium III Xeon processor delivers industry leading performance from its larger and faster L2 caches, multiprocessing capabilities and a 133- or 100- MHz system bus. Systems based on the Pentium III Xeon processor are scalable, with support for:
  • Up to two processors using "glueless" multiprocessing capabilities for processors using a 133-MHz system bus
  • Up to four processors using "glueless" multiprocessing capabilities for processors using a 100-MHz system bus
  • Larger than four-way systems using advanced chipsets or clustering technologies like NUMA and VI architecture for processors using a 100-MHz system bus
  • Support for 64B of system memory using expanded 36-bit addressing
The table below lists key features of the Pentium III Xeon processor.

Boxed Pentium® III Xeon™ Processor Product Feature Summary

Core Speeds (MHz) 10002 9332 900 8662 800 733 700 667 600 550 500
0.18 Micron Process Technology X X X X X X X X X    
0.25 Micron Process Technology                   X X
256KB Full-Speed L2 Cache X X   X X X   X X    
512KB Full-Speed L2 Cache                   X X
1MB Full-Speed L2 Cache             X     X X
2MB Full-Speed L2 Cache     X       X     X X
133-MHz System Bus X X   X X X   X X    
100-MHz System Bus     X       X     X X
Dual-Processing Capability X X X X X X X X X X X
4-Way Processing Capability     X       X     X1 X1
Integrated System Management
Features via the System Management
Bus (SMBus)
X X X X X X X X X X X
Streaming SIMD Extensions X X X X X X X X X X X
Intel Processor Serial Number X X X X X X X X X X X
Dual Independent Bus Architecture X X X X X X X X X X X
Dynamic Execution Technology X X X X X X X X X X X
Intel MMX™ Media-Enhancement
Technology
X X X X X X X X X X X
1Note Some versions of the Boxed Pentium III Xeon processor have been tested only in systems based on the Intel 82440GX AGPset. These processors have unique test specification numbers. To identify these processors, see the Pentium III Xeon processor table located in Product Specifications and Comparisons.
2Note Currently validated with the Intel® SBT2 Server Board only.
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Boxed Pentium III Xeon Processor Contents
  • 1 GHz, 933 MHz, 866 MHz, 800 MHz, 733 MHz, 700 MHz, 667 MHz, 600 MHz, 550 MHz, or 500 MHz processor
  • Attached Passive Heatsink
  • Certificate of Authenticity
  • Intel Inside® Logo Sticker
  • 3-year Limited Warranty
Motherboard Selection
Motherboards used with Pentium III Xeon processors must meet Intel's published processor specifications. Motherboards that support the Pentium II Xeon processor may also support the Pentium III Xeon processor. Consult your motherboard manufacturer to ensure compatibility with the Pentium III Xeon processor.

Motherboards used with the Pentium III Xeon processor 1 GHz, 933 MHz, 866 MHz, 800 MHz, 733 MHz, 667 MHz, or 600 MHz must support a 133 MHz system bus. Motherboards based on Intel's 840 AGPset should support a 133-MHz system bus.
Note 133 MHz system bus based Pentium III Xeon processors have only been validated for use in single or dual-processor motherboards.
In addition, motherboards used with the Pentium III Xeon processor 700 MHz, 550 MHz or 500 MHz must support a 100 MHz system bus. Motherboards based on Intel's 82440GX and 82450NX chipsets should support a 100 MHz system bus.
Note Some versions of the Boxed Pentium III Xeon processor have been tested only in systems based on the Intel 82440GX AGPset. These processors have unique test specification numbers. To identify these processors, see the Pentium III Xeon processor table located in the Product Specifications and Comparisons tool document.
Motherboards must be able to accommodate the processor's BIOS and electrical requirements. For BIOS compatibility, consult your motherboard manufacturer to ensure the board includes proper BIOS support for the Pentium III Xeon processor. The Pentium III Xeon processor's electrical requirements may be more stringent than those for the Pentium II Xeon processor. Consult your motherboard manufacturer to ensure your board meets the electrical requirements of the Pentium III Xeon processor.

Intel offers five boxed platforms (motherboard and chassis) for system integrators building systems using the 100 MHz system bus based Pentium III Xeon processors: the SC450NX, the C440GX+, the SPKA4, and the SRKA4. There is also one boxed platform using the 133 MHz system bus based Pentium III Xeon processors: the SBT2. These platforms meet all of the Pentium III Xeon processor system bus, BIOS, and electrical requirements mentioned above (see individual product pages for supported processors).

To build multiple processor systems, integrators are encouraged to choose a motherboard from a vendor that has a history of producing quality dual- or quad-processor motherboards. If you may need to mix processor steppings, consult your motherboard vendor for compatibility information.
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Chassis Selection
Selection of a proper chassis is a very important consideration - particularly to ensure that proper venting and good airflow are present so that the processor does not exceed its thermal limits. Your motherboard manufacturer may have recommendations for a chassis that provides an effective cooling solution with your particular motherboard. Chassis may need additional fans to ensure good airflow through the system. See the section entitled Thermal Management Considerations for more guidelines on selecting the appropriate chassis and performing thermal testing for your particular motherboard.

Integrators are encouraged to choose a chassis that will allow them to meet the thermal requirements of the processor. For assured compatibility, Intel's two boxed motherboards supporting the Pentium III Xeon processor, the C440GX, and the SBT2, can be purchased complete with a chassis that will accommodate the motherboard. These motherboard/chassis combinations have shown to provide an effective cooling solution for all system components, including the processor, in a typically loaded configuration.
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Processor Connector Requirements
Motherboards supporting the Pentium III Xeon processor feature a 330-contact slot connector (previously called Slot 2) into which the processor is inserted. Processors using a 330-contact slot connector permit a closely coupled, high speed L2 cache, high-frequency signal integrity, and headroom for processor technology evolution.

Motherboards with more than one 330-contact slot connector may come with a termination card. For proper operation, this termination card must be inserted into any slot not occupied by a processor.

Motherboards using a Pentium III Xeon processor require a mechanical support for the processor called a retention mechanism. The retention mechanism holds the processor securely in the 330-contact slot connector and protects the processor and motherboard from damage. Motherboards with a dual processor design may require a dual retention mechanism. The single or dual retention mechanism is not included with the Boxed Pentium III Xeon processor. Your motherboard supplier should provide the single or dual retention mechanism, along with installation instructions. (All Intel boxed motherboards that support the 330-contact slot connector include an appropriate retention mechanism.) Figure 1 shows a second processor being installed in a dual retention mechanism.

Pentium(R) III Xeon(TM) processor and Heatsink Being Installed into a DRM

Figure 1. Second Pentium III Xeon Processor and Heatsink Being Installed into a Dual Retention Mechanism
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Electrical Requirements
The Pentium III Xeon processor core and L2 cache may operate at different voltages, and each has different current requirements. The core and L2 cache are specified to operate at the following voltages and currents:
Boxed Pentium III Xeon Processor Electrical Specifications
Processor Frequency (MHz) and L2 Cache Size Processor Core Voltage, Current1 L2 Cache Voltage, Current Voltage Tolerance
500/512KB 2.0V, 14.0A 2.7V, 3.4A ± 0.085V
500/1MB 2.0V, 14.0A 2.0V, 14.0A ± 0.085V
500/2MB 2.0V, 14.0A 2.0V, 6.0A ± 0.085V
550/512KB 2.0V, 15.4A 2.0V, 3.5Av ± 0.085V
550/1MB 2.0V, 15.4A 2.0V, 3.5A ± 0.085V
550/2MB 2.0V, 15.4A 2.0V, 6.3A ± 0.085V
600/256KB 5V, 5.3A
12V, 2.2A
N/A
N/A
± 0.25V
± 0.6V
667/256KB 5V, 5.7A
12V, 2.4A
N/A
N/A
± 0.25V
± 0.6V
700/1MB 2.8V, 13.9A N/A ± 0.085V
700/2MB 2.8V, 13.9A N/A ± 0.085V
733/256KB 5V, 6.0A
12V, 2.5A
N/A
N/A
± 0.25V
± 0.6V
800/256KB 5V, 6.6A
12V, 2.7A
N/A
N/A
± 0.25V
± 0.6V
866/256KB 5V, 7.5A
12V, 3.2A
N/A
N/A
± 0.25V
± 0.6V
933/256KB 2.8V, 17 A
5V, 10.3 A
12V, 4,3 A
N/A
N/A
N/A
± 0.085V
± 0.250V
± 0.600V
866/256KB 5V, 7.9A
12V, 3.3A
N/A
N/A
± 0.25V
± 0.6VV
1000/256KB 5V, 7.9A
12V, 3.3A
N/A
N/A
± 0.25V
± 0.6V

1Core voltage for 600 MHz and higher with 133 MHz system bus can be either 5V or 12V. Current values in the table are maximum values, assuming the core voltage is at its tolerated minimum.

Pentium III Xeon processors 600 MHz and higher contain an On-Cartridge Voltage Regulator (OCVR). Intel manufactures two versions of the Pentium III Xeon processor with OCVR - one with a 2.8V input, and one with a 5V/12V input. The boxed Pentium III Xeon processors 600 MHz and higher with a 133 MHz system bus can accept either a 5V or 12V input at its core voltage pins. For these processors, the core VID pins are disabled in order to turn off the voltage regulator in motherboards that do not support the processor. Also, since the L2 cache is integrated on-die, the cache VID pins are set to 11111, which disables any motherboard-based L2 cache voltage regulator, which is no longer needed. Ensure that your motherboard specifically supports the 5V/12V version of the Pentium III Xeon processor before installing the processor.

For Pentium III Xeon processors 550 MHz and lower and the 700 MHz, proper core and L2 cache voltages must be supplied for reliable operation. In order to support the different voltages and currents, the processor contains five voltage identification pins for the core and five for the L2 cache. Ideally, two separate voltage regulators are needed, one for the core and one for the L2 cache. These voltages may be supplied by regulators integrated in the motherboard or by voltage regulator modules (VRMs) installed on the motherboard in VRM headers. Voltage regulators must also be able to supply the appropriate current for the core and L2 cache. Intel strongly recommends the use of voltage regulators that meet the VRM 8.3 specification. Some voltage regulators may be able to supply the appropriate voltages, but are not rated to supply the appropriate current. Consult your motherboard manufacturer to ensure your motherboard can accommodate the current and voltage requirements of your processor.

If the motherboard has VRM 8.3 headers, then a VRM must be installed in each header to power the associated processor's core or L2 cache. Most VRMs are VID-programmable. If your motherboard has fixed-voltage VRMs, the output voltages must match the processor core or L2 cache voltage requirements.

Since the operating voltages of Pentium III Xeon processors (both core and L2 cache) may be changed as the processor goes through stepping changes, VID-programmable voltage regulators, whether integrated or in VRM headers, are the preferred solution.
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Thermal Management Considerations
The table below shows the maximum operating temperatures for Pentium III Xeon processors, measured at the center of the processor's thermal plate beneath the heatsink:
Boxed Pentium III Xeon Processor Thermal Specifications
Processor Frequency (MHz) and L2 Cache Size Processor Stepping Max. Operating Temp. in °C Total Max Processor Power in Watts
500/512KB C0 75 36.0
500/1MB C0 75 44.0
500/2MB C0 75 36.2
550/512KB C0 68 34.0
550/1MB C0 68 34.0
550/2MB C0 68 39.5
600/256KB A2 55 21.6
667/256KB A2 55 23.9
700/1M A1 65 32.0
700/2M A1 65 32.0
733/256KB A2 55 26.2
800/256KB A2 55 28.5
866/256KB B0 55 30.8
900/2MB (2.8 V) B0 65 39.3
900/2MB (5V/12V) B0 65 40.8
933/256KB B0 55 33.2
1000/256KB C0 55 34.6

You must use a chassis that provides sufficient airflow to keep the processor under its maximum operating temperature in the warmest user environment. Running the processor above its maximum temperature specification will void the warranty and can lead to functional and performance degradation.

Motherboard configurations (processor connector location and orientation) vary and have a great impact on your choice of chassis. Contact your motherboard manufacturer for recommendations for chassis that provide an efficient cooling solution for your particular motherboard. Your cooling solution may also require additional chassis fans, and in some cases, retention mechanism fans.

Generally, Intel recommends the use of ATX 2.01-compliant motherboards and chassis or the new WTX form factor motherboards and chassis for efficient cooling.

Be aware that the airflow in non-ATX 2.01-compliant chassis varies significantly-depending on venting, internal brackets and other factors. Chassis with low airflow can cause processors to run warmer than their maximum specification.

Thermal evaluation should always be performed when selecting a chassis for Pentium III Xeon processor-based systems. The Pentium III Xeon processor has a Thermal Sensor and Thermal Reference Byte, both of which can be accessed via the processor's System Management Bus (SMBus). A thermal byte (8-bit number) can be read from the Thermal Sensor and compared to the Thermal Reference Byte to determine if the processor's cooling solution and environment are adequate. The Thermal Reference Byte contains a reference number that corresponds to the thermal byte reading when the processor's thermal plate temperature is at its maximum rating.

The passive heatsink on the boxed Pentium III Xeon processor (this does not apply for the special heatsinks produced for 866 MHz and greater) contains features that allow attachment of a standard 40mm auxiliary fan (with 36mm mounting hole spacing) or 50mm auxiliary fan to the heatsink face, providing a flexible cooling solution. This flexible solution allows processors in chassis environments with high localized airflow to use only the passive heatsink, and for processors in less efficient environments to be cooled with an optional attached fan. An auxiliary fan is not included with the boxed Pentium III Xeon processor, but can be purchased from most electronic parts suppliers. The boxed Pentium III Xeon processor ships with grommets and screws that allow an auxiliary fan to be attached to the heatsink face. Thermal analysis, as described above, should be done to determine the best cooling solution for each processor in your system.

Boxed Pentium(R) III Xeon(TM) processor With Optional Auxiliary Fan Aligned For Attachment

Figure 2: Boxed Pentium® III Xeon™ Processor
With Optional Auxiliary Fan Being Attached
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Dual and Multi-Processor System Considerations
In addition to single-processor use, the Pentium III Xeon processor is designed for dual and multiprocessor operation.

Pentium III Xeon processors based on a 133-MHz system bus have been validated to work only in a single- or dual-processor configuration. Pentium III Xeon processors based on a 100-MHz system bus is designed for up to 4-way processing.
Note Some versions of the Boxed Pentium III Xeon processor have been tested only in systems based on the Intel 82440GX AGPset. These processors have unique test specification numbers. To identify these processors, see the Pentium III Xeon processor table located in the Product Specifications and Comparisons tool document.
Pentium III Xeon processors are tested during manufacturing to ensure they will work in configurations with multiple processors of the same speed and same L2 cache sizes. While operation with different speed processors and different L2 cache sizes is not prohibited, it is not tested by Intel and could have implications when running with operating systems that support multiprocessing.

Intel tests multiprocessor configurations with different steppings of the Pentium III Xeon processor as new processor steppings are introduced. Certain Pentium III Xeon processors of the same speed but different steppings can be mixed in multiprocessor configurations.

Recommendations for Integration of Dual and Multiprocessor Systems:
  1. Ship multiprocessor systems with all processor slots populated to ensure that processor speeds, steppings, and L2 cache sizes are the same. When partially populated systems are shipped, customers attempting to install additional processors may have difficulty locating them with the same stepping or cache sizes. In these cases, they may have to replace the original processor to obtain a system with processors of the same stepping.
  2. If a system is shipped without all processors installed, test the system first with all processor slots populated. This will demonstrate whether the motherboard supports multiprocessor operation. You should also provide these customers with speed and stepping information for the original processor. This will ensure they understand the importance of having processors of the same speed, stepping, and cache size. It also warns them of the risk of having to replace the original processor in the future if earlier stepping processors are not available.
  3. If a system is shipped without all processors installed, make sure to install the appropriate termination card(s) in any vacant SC-330 connectors. Termination cards should be supplied with your dual- or quad-processor motherboard, or can be obtained from your motherboard vendor. All AGTL+ system bus signals must be terminated at each processor, so a vacated SC-330 connector must be populated with a termination card to maintain proper system bus termination.
    Note Termination cards for 133-MHz system bus based boards may differ from those for 100-MHz system bus based boards. Do not use termination cards interchangeably between boards. Consult your motherboard vendor for a termination card designed specifically for your motherboard.
  4. If a system is shipped without all processors installed, install the operating system with all processors installed. Some operating systems will install different kernel versions, depending on the number of processors present. Once the operating system has been installed the remaining processors can be removed before system shipment. This alleviates the need to reinstall the operating system if more processors are added later. Make sure to populate all open processor connections with appropriate termination cards, which should have been supplied with your motherboard.

How to Match Processor Steppings
The easiest way to match steppings is to compare the 5-character test specification numbers on the top of Pentium III Xeon processors. The number starts with an "S" and is followed by 4 characters (for example, "SL2RH"). Boxed Pentium III Xeon processors have the test specification number also printed on the package label.

Identical silicon steppings may sometimes be shipped with different test specification numbers-depending on whether they are for OEMs or for system integrators. Some Intel boxed processors may have OEM test specification numbers.

Boxed Pentium III Xeon Processor Silicon Test Specification vs. OEM Test Specification
Test specification numbers for the Pentium III Xeon processor can be found in the Pentium III Xeon processor table located in the Product Specifications and Comparisons tool.
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Mixing Processor Steppings and Speeds
Intel Corporation fully supports mixed steppings of Pentium III Xeon processors. The following list describes the requirements to support mixed steppings:
  • Mixed steppings are only supported with processors that have identical family and model numbers as indicated by the CPUID instruction.
  • While Intel has done nothing to specifically prevent processors operating at differing frequencies from functioning within a multiprocessor system, there may be uncharacterized errata that exist in such configurations. Intel does not support such configurations. In mixed stepping systems, all processors must operate at identical frequencies (i.e., the highest frequency rating commonly supported by all processors).
  • While there are no known issues associated with mixing of processors with differing cache sizes in a multiprocessor system, and Intel has done nothing to specifically prevent such system configurations from operating, Intel does not support such configurations since there may be uncharacterized errata that exist. In mixed stepping systems, all processors must be of the same cache size.
  • While Intel believes that certain customers may wish to perform validation of system configurations with mixed frequency or cache sizes, and that those efforts are an acceptable option to our customers, customers would be fully responsible for the validation of such configurations.
  • The workarounds identified in the latest specification update must be properly applied to each processor in the system. Certain errata are specific to the multiprocessor environment and are identified in the Mixed Stepping Processor Matrix, found in the Product Specifications and Comparisons tool. Errata for all processor steppings will affect system performance if not properly worked around. See the Pentium® III Xeon™ Processor Specification Update for details on processors that are affected by specific errata.
  • In mixed stepping systems, the processor with the lowest feature-set, as determined by the CPUID Feature Bytes, must be made the Bootstrap Processor (BSP). In the event of a tie in feature-set, the tie should be resolved by selecting the BSP as the processor with the lowest stepping as determined by the CPUID instruction. You motherboard BIOS should automatically perform this selection process. Contact your motherboard vendor if you have questions regarding your motherboard meeting this requirement.
Due to the variety of motherboard vendors in the market and the number of system BIOS revisions, some system-level issues may occur that lie outside the realm of any mixed stepping evaluation performed by Intel. Recommendations for shipping systems that mix Pentium III Xeon processor steppings are as follows:
  • Choose a motherboard vendor with a history of quality and dual and multiprocessor experience to minimize potential system-level issues.
  • Contact your motherboard vendor for information on mixed stepping validation performed on your particular dual or multiprocessor motherboard.
  • Refer to the General Information section of thePentium III Xeon Processor Specification Update for the latest information on mixed steppings. The specification update also contains information on processor errata, their workarounds and potential performance issues. The specification update can also be obtained from Intel literature at 1-800-548-4725.
Additional information related to stepping, voltage, and packaging of each specific boxed Pentium III Xeon processor can be found in the Pentium III Xeon Processor Quick Reference Guide.



This applies to:

Intel® Pentium® III Xeon® Processor



Solution ID: CS-022664
Last Modified: 26-Jul-2010
Date Created: 04-May-2006
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