Processors
Intel® Pentium® III Processor
Integration notes

The Boxed Intel® Pentium® III Processor

General Information

Performance
The Intel® Pentium® III Processor offers top performance for today and tomorrow's applications as well as quality, reliability, and compatibility from the world's leading microprocessor company. Users can expect excellent PC software performance and full compatibility with Intel Architecture-based software. Processing power is extended to allow for higher performance of business media, communication, and Internet capabilities. Web sites designed with the Intel Pentium III Processor in mind will unleash the full multimedia capabilities of the processor, which leads to an enhanced, exciting Internet experience.

Technology
The Intel Pentium III Processor integrates the best attributes of the P6 microarchitecture processors: Dynamic Execution, a multi-transaction system bus, and Intel MMX™ media enhancement technology. For an enhanced Internet experience, the Intel Pentium III Processor offers Internet Streaming SIMD Extensions, 70 new instructions enabling advanced imaging, streaming audio and video, speech recognition, and 3-D. The Intel Pentium III Processor also incorporates the processor serial number. The 96-bit serial number is accessible through the CPUID instruction and can be used by software applications to identify a system. Note: This feature can be legally disabled at the BIOS level. See the Loading a Processor Serial Number Control Utility section for more details.

The Intel Pentium III Processor also incorporates Dual Independent Bus architecture. Two buses make up the Dual Independent Bus architecture: (1) L2 cache bus and (2) processor-to-main-memory system bus. The Intel Pentium III Processor can use both buses simultaneously, achieving more than two times the data in or out of the Intel Pentium III Processor than a single bus architecture processor. The system bus provides increased bandwidth for today's newer, demanding technologies, such as the Accelerated Graphics Port (AGP). The Dual Independent Bus architecture enables the closely coupled L2 cache of the Intel Pentium III Processor to run more than four times as fast as the L2 cache on Pentium processor-based systems. Finally, the pipelined system bus enables multiple simultaneous transactions (instead of singular sequential transactions), accelerating the flow of information within the system and boosting overall performance. All Intel Pentium III Processors use the Error Checking and Correction (ECC) protocol on the L2 cache bus. Since ECC protocol is a more comprehensive method of ensuring data integrity, it can detect both single-bit and double-bit errors and correct single-bit errors automatically.

Platform Initiatives
The latest addition to the IA-32 processor line is the Intel Pentium III Processor manufactured on 0.13 micron technology. This manufacturing process technology is coupled with an on-die full-speed advanced transfer L2 cache and enables a new form factor. Boxed Intel Pentium III Processors are now available in two package options: (1) Single Edge Contact Cartridge 2 (S.E.C.C.2) and (2) Flip Chip Pin Grid Array (FC-PGA) package, and (3) Flip Chip Pin Grid Array2 (FC-PGA2) Package. The FC-PGA package is designed for the new breed of sleek, high performance, small form factor PCs. The FC-PGA2 package is an FCPGA package with the addition of an integrated heat spreader (IHS). The HIS provides improved package thermal cooling characteristics for higher speed Intel® Pentium® III Processors without having to use a larger heat sink.

Table 1. Boxed Intel® Pentium® III Processor Product Feature Summary

Core Speeds (MHz) / Versions 1.13-1.40 GHz-S 1.20 1.13 GHz 1 GHz (IHS) 1 GHz 1.0 933
900
866
800EB
733
667
600EB
533EB
850
800
750
700
650
600E
550E
600B
533B
550E
500E
600
550
500
450
FC-PGA2 Package (Integrated Heat Spreader) x x x
S.E.C.C.2 Package x x x x x
FC-PGA Package x x x x
0.13µ Process Technology x x
0.18µ Process Technology x x x x x
0.25µ Process Technology x x
133-MHz System Bus x x x x x x
100-MHz System Bus x x x x
Dual Processing Capable x x x x x x x
512KB On-Die Full-Speed L2 Cache x
256KB On-Die Full-Speed
L2 Cache
x x x x x
512KB On-Package Half-Speed L2 Cache x x
Streaming SIMD Extensions x x x x x x x x x
Intel Processor Serial Number x x x x x x x x x
Dual Independent Bus Architecture x x x x x x x x x
Dynamic Execution Technology x x x x x x x x x
Intel MMX™ Media- Enhancement Technology x x x x x x x x x
Version Designators: B = Intel® Pentium® III Processors that operate with a 133-MHz system bus.
E = Intel Pentium III Processors that have the new on-die full-speed advanced transfer L2 cache.
EB = Combination of B and E characteristics.
The 800 EB MHz processor has a 133-MHz system bus.
The 800 MHz processor has a 100-MHz system bus.
Note Both 800 and the 800EB have the new on-die full-speed Advanced Transfer Cache.

The 1 GHz processor available in the S.E.C.C.2 package is only validated for use in the L440GX+ server board and has a 100-MHz system bus. The 1.0B GHz processor available in the S.E.C.C.2 package is only validated for use with a special version of the Intel® Desktop Board VC820 (custom VRM) and Kingston* RDRAM. It has a 133-MHz system bus.

Integrating Boxed Intel® Pentium® III Processor-Based Systems

Motherboard Selection

Overview
Motherboards used with the boxed Intel Pentium III Processor must specifically support the processor type and core speed. Some older motherboards may not support all speeds of the boxed Intel Pentium III Processor. Using a boxed Intel Pentium III Processor in a motherboard that does not support its current electrical requirements can cause permanent damage to the motherboard. Some older motherboards will require BIOS upgrades in order to properly recognize and setup the Intel Pentium III Processor. Using a Intel Pentium III Processor with the incorrect BIOS revision may cause a system to be unstable. Verify that the specific motherboard and BIOS revision will support the Intel® Pentium® III Processor. Motherboards used with Intel Pentium III Processors must meet Intel's published processor specifications.

To ensure compatibility, Intel offers boxed boards for system integrators in ATX and microATX form-factor designs for use with the boxed Intel Pentium III Processor.

Fan Heat sink Requirements
The boxed Intel Pentium III Processor is delivered with a fan heat sink specially designed to provide efficient cooling in a variety of thermal environments. The fan power cable must be connected to the fan power connector and the motherboard power header as shown in the processor installation notes (included in the boxed processor package).

The motherboard 3-pin power header uses two pins to supply +12V and GND. The fan uses the third pin to transmit fan-speed information to motherboards that support fan-speed detection. Your motherboard must have a 3-pin fan power header located close to the slot or socket. Refer to your motherboard manual for the location of the power header.

Voltage Requirements
Intel Pentium III Processors are specified to operate at the voltages listed in Table 2.

Table 2. Voltage Requirements for Intel® Pentium® III Processors

Nominal Core Voltage (Volts) Core Speed (MHz) Form Factor Stepping
2.05 V 600, 600B S.E.C.C.2 kC0
2.00 V 450, 500, 533, 550 S.E.C.C.2 kB0, kC0
1.76 V 1B GHz1,2 FC-PGA cC0
1.75 V 866, 933, 1.0 B GHz1 FC-PGA cD0
1.70 V 550E, 600E, 600EB, 650, 667, 700, 733, 750, 800, 800EB, 850, 866, 900, 933, 1.0 B GHz1 FC-PGA cC0
533EB, 550E, 600E, 600EB, 650, 667, 700, 733, 750, 800, 800EB, 850, 866, 933, 1.0 GHz1 1.0 B GHz1 S.E.C.C.2 cC0
933, 1 B GHz FC-PGA cB0
933, 1 GHz1, 1.0 B GHz1 S.E.C.C.2 cB0
1.65 V 533EB, 550E, 600E, 600EB, 650, 667, 700, 733, 750, 800, 800EB, 850, 866 S.E.C.C.2 cA2, cB0
533EB, 600E, 600EB, 650, 667, 700, 733, 750, 800, 800EB, 850, 866, 933 FC-PGA cA2, cB0
550E FC-PGA cB0
1.60 V 500E FC-PGA cA2, cB0
500E FC-PGA cA2
1.45 V 1.13 GHz-S, 1.20 GHz-S3, 1.40 GHz-S3 FC-PGA2 tA1
1.475 V 1.13, 1.20 GHz FC-PGA2 tA1
  1. Note that 1 GHz = 1000 MHz
  2. This only affects processors with the s-spec, SL4WM. The SL4WM s-spec has a VID request of 1.70V, however, the processor should be supplied 1.76V at the PGA Vcc pins.
  3. The Intel® Pentium® III Processor-S with 512 KB cache is designed for server platforms only. Using this processor in a desktop motherboard will cause the processor to operate out of specification and void the limited 3-year warranty for the boxed processor. Therefore, when using this processor, make sure that the motherboard is supports processors based on .13µ process technology and 512 KB cache. These processor should not be used with motherboards based on the Intel 440BX, 810, 815, 820 and 840.

Caution Verify that the motherboard supports the specific processor stepping and speed, as well as providing the required voltage.

Proper voltage must be supplied for reliable operation. Voltage may be supplied by a regulator integrated on the motherboard, or by a voltage regulator module (VRM) installed in Header 8 on the motherboard.

If the regulator is integrated on the motherboard, it must be Voltage ID (VID) programmable to allow the processor to program the correct voltage during power-on. If the motherboard has Header 8, then a VRM must be installed in the header to power the processor. Most VRMs are VID-programmable. If your motherboard has a fixed-voltage VRM, its output voltage must match the processor requirements.

Since the operating voltage of Intel Pentium III Processors may change as the processor goes through stepping changes, VID-programmable voltage regulators are the preferred solution. For complete voltage specifications for Intel Pentium III Processors, refer to the Intel® Pentium® III Processor Data sheet.

Chassis Selection
Intel encourages integrators using ATX form-factor boards. Choose a chassis that complies with the ATX specification (version 2.01 or later). A copy of the most current ATX specification appears on the Form Factor Web site. The site also lists ATX chassis manufacturers.

Integrators using microATX form-factor motherboards should choose a chassis that complies with the microATX specification (version 1.0). A copy of the most current microATX specification appears on the Form Factor Web site. The site also lists microATX chassis manufacturers.

In addition, Intel tests chassis for compatibility with boxed Intel Pentium III Processors and Intel Desktop Boards for system integrators.

Thermal Management Considerations

Thermal testing should always be performed when selecting a chassis for boxed Intel Pentium III Processor-based systems.

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.

Intel recommends the use of ATX 2.01 or later or microATX 1.0-compliant motherboards and chassis for proper mechanical fit. The combination of the fan heat sink shipped with the boxed Intel Pentium III Processor, an ATX or microATX form-factor motherboard, and an ATX or microATX-compliant chassis can be a good thermal management solution.

If you use Baby AT motherboards, be aware that the airflow varies significantly in different Baby AT chassis, depending on venting, internal brackets, and other factors. Chassis with low airflow can cause processors to exceed their maximum thermal specification.

Intel's tested chassis lists contain the names of chassis that have been tested by Intel. Listed chassis provide adequate airflow and ventilation to cool boxed Intel® Pentium® III Processors when installed in typically configured systems on Intel Desktop Boards. However, additional thermal testing is necessary for each system configuration, even when using a chassis on the tested chassis list.

Boxed Intel Pentium III Processor Installation Instructions

S.E.C.C.2 Package

Motherboard Mechanical Requirements

Motherboards supporting the boxed Intel Pentium III Processor feature a single-edge slot connector called the 242-contact slot connector. The boxed Intel Pentium III Processor in the S.E.C.C.2 package is inserted into this connector.

The boxed Intel Pentium III Processor requires mechanical support called retention mechanisms. Retention mechanisms hold the processor securely in the 242-contact slot connector, and protect it and the motherboard from damage. Retention mechanisms are not included with the boxed Intel Pentium III Processor. The motherboard supplier should provide retention mechanisms and installation instructions. (All Intel Desktop Boards that support the 242-contact slot connector include retention mechanisms.)

Some older motherboards may be shipped with retention mechanisms that only support the S.E.C.C. package and do not support processors in the S.E.C.C.2 package. Using a boxed Intel Pentium III Processor in the wrong retention mechanism will void the warranty. Contact the motherboard manufacturer to determine the processor support of the retention mechanisms provided with the motherboard.

Intel® Pentium® III Processor in the S.E.C.C.2 Package

Figure 1. Boxed Intel® Pentium® III Processor
in the S.E.C.C.2 Package

(fan power cable not shown)

Intel Pentium III Processor Installation and Removal Instructions

Installation and removal may vary slightly based on the retention mechanisms provided by the motherboard manufacturer. These guidelines assume the use of universal retention mechanisms. Installation into other types of retention mechanisms is similar. Motherboards shipped with retention mechanisms should have instructions on inserting the processor into the 242-contact slot connector.

Intel Pentium III Processor installation steps:

  1. Install the retention mechanism(s) onto the motherboard using the motherboard manufacturer's instructions.
  2. Install the processor into the 242-contact slot connector by applying force to the top of the processor and fan heat sink. Make sure to install the heat sink into the retention mechanism and the processor substrate into the 242-contact slot connector. Do not bend the processor package.
  3. Install the processor fan cable to the motherboard connector and the fan heat sink.
  4. Power on the system and verify that the processor fan is running.
  5. Shut down system.

Removal diagram

Figure 2. Boxed Intel® Pentium® III Processor
Removal Diagram

Intel Pentium III Processor removal steps: Refer to Figure 2, boxed Intel Pentium III Processor removal diagram. First pull one retention mechanism away from the processor with one hand while rotating the processor out of the 242-contact slot connector with the other hand. The retention mechanisms provide firm mechanical support for the processor.

Caution If you find that considerable force is required to remove the processor, consider wearing gloves to protect your hands and take care to keep your hands away from any metal edges on the chassis and processor package when removing the processor from the retention mechanisms. Loosening or removing one of the retention mechanisms greatly reduces the force required to remove the processor.

Note To loosen retention mechanisms with captive brass fasteners, simply unscrew the fastener with a screwdriver.

Removing retention mechanisms with plastic fasteners requires the removal of the motherboard from the chassis.

  1. After the motherboard is removed and while viewing the underside of the motherboard, use the tip of a ballpoint pen or other tool to carefully push the bottom of the white pin insert out of the black plastic fastener sleeve.
  2. After the white insert pins are removed, carefully push the black sleeve portion of the fastener out of the motherboard to free the retention mechanism.

FC-PGA2 Package
The FC-PGA2 package is an FCPGA package with the addition of an integrated heat spreader (IHS). The IHS provides improved package thermal cooling characteristics for higher speed Intel® Pentium® III Processors without having to use a larger heat sink. Besides those differences, the installation requirements are similar to the FC-PGA Package.

FC-PGA Package

Motherboard Mechanical Requirements

Motherboards supporting the boxed Intel Pentium III Processor in the FC-PGA package feature a socket called the 370-pin socket. The boxed Intel Pentium III Processor is inserted into this socket.

The Boxed Intel® Pentium® III Processor in the FC-PGA Package to 933 MHz The Boxed Intel® Pentium® III Processor in the FC-PGA Package at 1 GHz
Figure 3a: Boxed Intel® Pentium® III Processor in the FC-PGA Package to 933 MHz Figure 3b: Boxed Intel® Pentium® III Processor in the FC-PGA Package at 1 GHz or greater

Intel recommends motherboards equipped with the PGA370 socket for the boxed Intel Pentium III Processor in the FC-PGA package. The motherboard must be specifically for the Intel Pentium III Processors. However, if it is necessary to use a "slot-to-socket adapter (SSA)", follow these critical considerations and recommendations:

  1. The SSA must be recommended by the motherboard manufacturer for use with the boxed Intel Pentium III Processor and your selected motherboard.
  2. The SSA must operate the processor within Intel's electrical, mechanical, and thermal specifications.
  3. Intel does not validate SSAs for use with Intel branded boards or third-party motherboards.

Note Severe mechanical and electrical damage may occur to the processor, motherboard, or both if these recommendations and considerations are not carefully followed.

Integrating the boxed Intel Pentium III Processor in the FC-PGA package into SSAs that are designed for the Intel Celeron processor may damage the Intel Pentium III Processor. For specific validation of any SSA with your motherboard and processor, please check with your motherboard vendor.

Be aware of thermal considerations and mechanical requirements when installing any SSA. The fan heat sink included in the boxed processor package will provide sufficient cooling. However, this solution violates the maximum mechanical volumetric dimensions and weight restrictions that are recommended for motherboards with the 242-contact slot connector. Violating this recommendation will result in the SSA "leaning" to one side, which may cause broken electrical connections and interference with motherboard components. Therefore, system integrators using an SSA must follow two requirements when installing a boxed Intel Pentium III Processor.

  1. The SSA is electrically connected and mechanically held secure in the 242-contact slot connector (consider a SSA with a retention mechanism interface).
  2. No motherboard components are adversely affected by installing the boxed processor on the SSA.

Slot-to-Socket Adapter

Figure 4. Slot-to-Socket Adapter (SSA)
Installed into a Motherboard

How to install and remove the fan heat sink of the boxed Intel® Pentium® III Processor

For a detailed description on installing the boxed Intel® Pentium® III Processor, refer to the installation manual.

Intel® Pentium® III Processor with Metal Heat sink Clip
Intel® Pentium® III Processor with Plastic Heat sink Clip

Intel Pentium III Processor installation steps for metal heat sink clip:

  1. Raise the handle of the 370-pin socket.
  2. Carefully install the processor into the 370-pin socket making sure that none of the pins are bent.
  3. Close the handle of the socket.
  4. Next install the fan heat sink. Make sure to install the heat sink onto the processor after the processor has been inserted into the 370-pin socket. Place the fan heat sink onto the processor so that the integrated clip lines up with the socket's attach tabs and the fan cable aligns with the PGA370 mark on the 370-pin socket.
    Caution Take care to not damage the white thermal interface pad on the bottom of the heat sink.
  5. Locate the socket tab opposite the PGA370 mark on the socket. Latch the clip to this tab first.
  6. To attach the clip to the other socket tab, locate a standard #1, small flathead screwdriver and align with upper clip slot (Figure 5a - 'B').
  7. Insert screwdriver into clip slot. Extend (as shown in Figure 5a - 'D') the heat sink clip away from the socket tab (Figure 5a - 'C') by rotating the screwdriver upwards toward the fan heat sink (Figure 5a - 'A').
  8. Continue rotating the screwdriver upwards (as shown in Figure 5b - 'A') until the bottom edge of the clip clears the socket tab (Figure 5b - 'D').
  9. Slowly push down on the clip (as shown in Figure 5b - 'B') until it is lined up with the bottom edge of the socket (Figure 5b - 'C').
  10. Latch clip onto socket tab (Figure 5b - 'D').
    Caution Take care to not scrape the motherboard underneath the 370-pin socket attach tabs.
  11. Connect the integrated fan power cable to the motherboard connector.
  12. Power on the system just long enough to verify that the processor fan operates.

Install diagram Install diagram
Figure 5a: Step 1 of Boxed
Intel® Pentium® III Processor FC-PGA Install
Figure 5b: Step 2 of Boxed
Intel® Pentium® III Processor FC-PGA Install

Before removing the processor, consider removing the motherboard from the chassis.

Intel® Pentium® III Processor removal steps for metal heat sink clip:

  1. Unplug the fan power cable from the motherboard's connector.
  2. Follow installation steps 5-10 in reverse order.
  3. Use a #1, small flathead screwdriver to unlatch the integrated clip from the socket's tab nearest the fan cable.
  4. Insert screwdriver into upper clip slot. Push down on the clip and simultaneously rotate the screwdriver towards the fan heat sink (see Figure 5b).
  5. After the heat sink clip is free, slowly lift the fan heat sink straight up and away from the socket and the processor.
  6. Raise the handle of the 370-pin socket, and then carefully remove the processor from the socket.
    Caution Make sure to not bend any of the processor pins.

Intel® Pentium® III Processor installation instructions for the plastic heat sink clip:

  1. Raise the handle of the 370-pin socket.
  2. Carefully install the processor into the 370-pin socket making sure that none of the pins are bent.
  3. Close the handle of the socket (A). See Fig. 6a.
  4. Align the fan heat sink clip to the socket as shown in Fig. 6a. Make sure to align the pin on the heat sink clip (B) to the hole in the fan heat sink.
  5. Align the pin hole (C) with the PGA370 mark (D) on the socket. With the clip lever in the up position, install the fan heat sink on the processor.
  6. Make sure both sides of the clip (E) are securely fastened to the socket tabs (F). Close the clip lever.
    Note Be careful not the damage the thermal interface material when installing the heat sink onto the processor.
  7. Snap the fan on the heat sink as shown in Figure 6b.
  8. Connect the integrated fan power cable to the motherboard connector (G).
  9. Power on the system just long enough to verify that the processor fan operates.

Figure 6a: Step 1 of the Installation of the FC-PGA Boxed Intel® Pentium® III Processor at 1 GHz

Figure 6a: Step 1 of the Installation of the FC-PGA
Boxed Intel® Pentium® III Processor at 1 GHz

Figure 6b: Step 2 of the Installation of the Boxed FC-PGA Intel® Pentium® III Processor at 1 GHz Figure 6c: Removal of the Boxed FC-PGA Intel® Pentium® III Processor at 1 GHz
Figure 6b : Step 2 of the Installation of the Boxed FC-PGA Intel® Pentium® III Processor at 1 GHz
Figure 6c: Removal of the Boxed FC-PGA Intel® Pentium® III Processor at 1 GHz

IMPORTANT NOTE: If the fan is attached incorrectly, it may unlatch itself at a later time from normal jarring of the computer. If the fan detaches from the heat sink, the processor may be permanently damaged.

Please refer to figure 7a and 7b for the proper fan orientation. Notice the position of the Intel hologram and fan cable relative to the heat sink clip. Figure 1 is the incorrect fan orientation and figure 2 is the proper fan orientation. Furthermore, please make sure the fan is securely fastened to the heat sink by firmly pulling on the fan.

image of incorrect heat sink fan orientation image of correct heat sink fan orientation
Figure 7(a) shows the incorrect orientation of the heat sink fan, while Figure 7(b) shows the correct orientation of heat sink and fan.

Before removing the processor, consider removing the motherboard from the chassis.

Intel® Pentium® III Processor removal steps for plastic fan heat sink clip:

Intel Pentium III Processor removal steps:

  1. Unplug the fan power cable from the motherboard's connector.
  2. Remove the fan from the heat sink.
  3. Open the heat sink clip lever.
  4. Referring to Figure 6c, while holding onto the heat sink, slide (H) the heat sink (J) towards the socket tab (K) located on the cam lever side (L) of the PGA370 socket. The heat sink clip should pop free of the socket tab (K).
  5. After the heat sink clip is free, slowly lift the fan heat sink straight up and away from the socket and the processor.
  6. Raise the handle of the 370-pin socket, and then carefully remove the processor from the socket.
    Caution Make sure to not bend any of the processor pins.


Operating System and Application Support
The Intel Pentium III Processor is backward compatible with Intel Architecture compatible operating systems and applications. Many of the new Internet Streaming SIMD Extensions can be used by applications on any operating system provided the operating supports the instructions being used. Many modern operating systems have support for all instructions introduced with the Internet Streaming SIMD Extensions, but this support may require installation of specific drivers.

Applications that do not use the Internet Streaming SIMD Extensions will still benefit from the Intel Pentium III Processor's high-speed execution and P6 microarchitecture. Applications that use the Internet Streaming SIMD Extensions should verify proper operating system support for the extensions and may signal the installer if the operating system does not yet have the proper driver support.

Integrators building systems based on the Intel Pentium III Processor should choose an operating system that supports the Internet Streaming SIMD Extensions, install any necessary drivers, and verify the operating system is prepared for applications that are optimized with the Internet Streaming SIMD Extensions.

Loading a Processor Serial Number Control Utility
Computer system users should have control over which software or Web sites have permission to read the processor serial number from their system. This control can be provided by enabling or disabling the processor serial number in the BIOS through a setup option or in the operating system environment via a control utility. If either of these methods is set to "disabled," the processor serial number will not be available to software applications. The Intel processor serial number control utility is a program that enables or disables the reading of the processor serial number of the Intel Pentium III Processor in the Windows* 95, Windows 98 or Windows NT* operating system environments. Intel encourages system integrators to load a processor serial number control utility onto every Intel Pentium III Processor-based system built.

Dual Processor System Considerations
Intel Pentium III Processors are tested during manufacturing to ensure they will work in dual-processor configurations with processors of the same speed. Operation with different speed processors is not prohibited, but is not tested by Intel. Intel tests dual processor configurations with different steppings of the Intel Pentium III Processor as new processor steppings are introduced. For more information, see Mixing Processor Steppings below. Intel still recommends using processors of the same stepping when integrating dual processor systems.

Recommendations for Integration of Dual Processor Systems

  1. Ship dual-processor systems with both processors installed to ensure that processor speeds and steppings are the same. When partially populated systems are shipped, a customer returning for additional processors may have difficulty locating a processor with the same stepping. If this occurs, the customer may have to replace the original processor to obtain a system with two processors of the same stepping.
  2. If a system is shipped with only one processor installed, first test the system with both processors installed. This will demonstrate whether the motherboard will support dual-processor operation. Provide customers with the speed and stepping information of the original processor in these systems and make sure they understand the importance of having processors of the same speed and stepping. Warn customers 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 with only one processor, install the operating system with two processors installed. Some operating systems will install different kernel versions, depending on the number of processors present. The second processor can then be removed before system shipment. This technique alleviates the need to reinstall the operating system if a second processor is added later.
  4. Integrators that want to mix processor steppings within a dual-processor system should first read Mixing Processor Steppings below for an overview of the issues involved.

Matching Processor Steppings
The easiest way to match steppings is to compare the 5-character test specification numbers on the top of Intel® Pentium® III Processors. The number starts with an "S" and is followed by 4 characters (for example, "SL3CC"). Boxed Intel Pentium III Processors have the test specification number also printed on the box 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.

Mixing Processor Steppings
Even though Intel recommends using identical processor steppings in multiprocessor systems whenever possible (as this is the only configuration which receives Intel's full testing), Intel supports mixing processor steppings, and does not actively prevent various steppings of the Intel Pentium III Processor from working together in dual-processor systems. However, since Intel cannot test every possible combination of devices, each new stepping of a device is fully tested only against the latest steppings of other processors and chipset components.

With mixed stepping configurations, all processors must be run at an identical frequency. The workaround for various errata must take all processors into account. Errata for the Intel Pentium III Processor are published in the Intel® Pentium® III Processor Specification Update. Errata for all processor steppings present in a system will affect that system, unless worked around.

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 Intel Pentium III Processor steppings are as follows:

  1. Choose a motherboard vendor with a history of dual-processor experience.
  2. Contact your motherboard vendor for information on mixed stepping validation performed on your particular dual processor motherboard.

Refer to the Intel® Pentium® III Processor Specification Update for information on processor errata, their workarounds, and potential performance issues before integrating dual processor systems. The specification update can be obtained from Intel's Developer Site.

This applies to:

Intel® Pentium® III Processor



Solution ID: CS-007568
Last Modified: 28-Aug-2014
Date Created: 10-Dec-2003
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