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Date:      Wed, 24 Dec 2003 13:56:43 -0500
From:      Chuck Swiger <cswiger@mac.com>
To:        Gerard Samuel <fbsd-questions@trini0.org>
Cc:        questions@freebsd.org
Subject:   Re: Running dual CPUs
Message-ID:  <3FE9E16B.8010203@mac.com>
In-Reply-To: <200312240034.29237.fbsd-questions@trini0.org>
References:  <200312240034.29237.fbsd-questions@trini0.org>

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Gerard Samuel wrote:
> I acquired a pair of Slot 1 CPUs that is supposedly a matched pair.
> I've heard, that they must be of the same stepping, and Im not sure of what Im 
> looking for.

See page 12 of:

ftp://download.intel.com/design/PentiumIII/specupdt/24445349.pdf

...which discusses this issue in detail:

"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.

[ ... ]

• 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.  In the following processor matrix a number indicates that a 
known issue has been identified as listed in the table following the
matrix. A dual processor system using mixed processor steppings must assure 
that errata are addressed appropriately for each processor."

...and then provides twenty pages worth of charts, notes, and whatnot. :-)

[ If you get a chance, try to upgrade to Tualatin P3's, with the full-speed L2 
cache and SSE. ]

-- 
-Chuck



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