Archived from groups: alt.comp.hardware.pc-homebuilt (
More info?)
nubis wrote:
> On Sat, 14 Aug 2004 20:38:28 -0500, David Maynard <dNOTmayn@ev1.net>
> wrote:
>
>
>>nubis wrote:
>>
>>
>>>I have two p3 slot 370 motherboards with 866 cpus and was considering
>>>buying a dual processor motherboard. The cpus were bought at
>>>different times and was wondering if that would be a problem with them
>>>working in the dual cpu motherboard. Thanks
>>
>>I don't know off the top of my head if there are any 'newer' steppings for
>>the 866 than shown in my Dec 2002 update but as far as P-III 866 cB0 and
>>cC0 goes there are no known issues pairing them, as of Dec 2002 that is.
>
>
> Thanks. I've been reluctant to get a dual cpu board due to the
> compatibility issue. What I had read in the past - cpus had to be
> batch-paired in order for both to work on the board.
Yes, people often say that but Intel has, for as long as I can remember,
provided an SMP pairing table in their specification update sheets.
For your edification, here is the exact wording pasted from the Intel sheets
Mixed Steppings in DP Systems
Intel Corporation fully supports mixed steppings of Pentium III processors.
The following list and processor matrix describes the requirements to
support mixed steppings:
• Mixed steppings are only supported with processors that have identical
family and model number 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 the mixing of processors
with differing cache sizes in a dual processor 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 dual processor 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 this and following specification updates
must be properly applied to each processor in the system. Certain errata
are specific to the dual processor environment and are identified in the
Mixed Stepping Processor Matrix found at the end of this section. Errata
for all processor steppings will affect system performance if not properly
worked around. Also see the “Pentium® III Processor Identification and
Package Information” table for additional details on which processors are
affected by specific errata.
• In dual processor systems, the processor with the lowest feature-set, as
determined by the CPUID Feature Bytes, must be 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.
The Matrix for 866MHz P-IIIs had "NI" for each combination of cB0 and cC0
in Slot-1 and the same for FC-PGA packages (by that I mean there is no
mixing of FC-PGA with Slot-1) with the explanation of:
NI= Currently no known issues associated with mixing these steppings.
> It's probably
> the cheapest upgrade for me since P4 means the works.
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