On 19 Aug 99, at 19:41, Derek Buchanan wrote:

>   I have a question for the gurus of the list.  I have heard that Celeron
> chips from Intel are chips that were defective Pentium III s with there
> internal cache shut off or reduced to 128 to operate.  Cache was then
> placed on the motherboards to compensate for this malfunction.  Is this
> true?

  NO.  The first Celerons had no cache, but none was ever added to
motherboards to support them.  Although Celerons retain the multi-processor
support inherited from the PII core design (disconnected by Intel but
relatively easy to reconnect), they have neither the 77 additional instruction
codes nor the embedded ID number that distinguish a PIII from a PII.
  It might have been possible for some of the earliest Celerons to have been
fabricated as PII CPUs but mounted without cache.  However, since cache was
added with the Celeron 300A, it has been smaller, faster, and attached
differently from the cache in PII/PIII CPUs, such that Celerons with cache
cannot possibly have started life as "defective Pentium III s".

>   I was told this by a fairily knowledgable computer person.  I
> would like to confirm the truthfulness of this statement before I pass
> this information on to other people that ask me about Celeron chips.

  It is possible that the first 486SX CPUs were 486DX with defective/disabled
FPUs, but as demand increased, it became very unlikely that Intel could
profitably meet that demand this way.  There may have been a time when a few
defective PIIs could have been salvaged by packaging as Celerons, but that
time has passed.

  Could it ever have been an option for PIIIs?  I don't think so.  Intel
revealed at one point that a few high-end "mobile PII" CPU versions have the
serial number mechanism like the PIII's included, but I've seen no reports of
this amongst any of the Celeron models.


David G

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