Intel® Pentium® II Processor
Dual Processors

End of interactive support
Intel is announcing the end of interactive support for the Pentium® II processors. See the End of Interactive Support Announcement for details.

Though Intel recommends using identical steppings of processor silicon in multiprocessor systems whenever possible (as this is the only configuration which receives full validation across all of Intel's testing), Intel supports mixing processor steppings, and does not actively prevent various steppings of the Pentium® II processor from working together in DP systems. However, since we cannot validate every possible combination of devices, each new stepping of a device is fully validated only against the latest steppings of other processors and chipset components.

A processor with a C0 core stepping, or with a CPUID of 6-3-3, is not validated for mixed stepping operation.

The lowest common denominator is required when configuring the system. In mixed stepping configurations, all processors must be run at the lowest frequency. If one processor has ECC capable L2 cache, and the other does not, ECC must be disabled.

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 Pentium II processor steppings are as follows:

  • Choose a motherboard vendor with a history of quality and DP experience to minimize potential system-level issues.
  • Make sure that the motherboard's BIOS will support all processor steppings. Motherboard vendors should be able to supply information about the steppings of the Pentium II processor supported by the BIOS on a specific motherboard.
  • Refer to the Pentium® II Processor Specification Update for information on Pentium® II processor errata, their workarounds, and potential performance issues before integrating dual processor systems.

In order to see any significant benefit from a dual processor configuration, you would first need an operating system that supports more than one processor. Microsoft* Windows NT*, some varieties of Unix*, and BeOS* are examples of those that do.

You would also need applications that are multithreaded. In other words, the code for the programs is able to separate into threads for execution on more than one processor. Not many can do this, so I would suggest that you confirm this with the manufacturers of the applications that you wish to use.

The Pentium II Processor Specification Update can be downloaded from:

This applies to:

Intel® Pentium® II Processor

Solution ID: CS-011179
Last Modified: 06-Oct-2014
Date Created: 14-May-2004
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