🚀 go-pugleaf

In article <1icegqINN7vl@savoy.cc.williams.edu>, 93gke@williams.edu (oldwanda) writes:
|> If this is true, then how can vendors push the 25Mhz chips to 33Mhz?
|> Wouldn't they fail at the higher speeds since they were slow in
|> testing?
|> 
1st there is a guard band.  I.e. a 25MHz grade are usually tested to pass
say 28MHz in all it's tests.  Since I do not work for Intel, I do not 
know what guard band they set.

2nd, there are numerous test on different parts of the chips switching
speed.  Again, not knowing the 486 intimately, let's assume there are
100 such tests.  Maybe 99 of them meet the 33MHz grade but one of them
do not. These would drop the chip the 25MHz grade.  What if that 1
test exercises a seldomly used instruction?  The failure of running
this chip at 33MHz would then be rare.
 
3rd, semiconductors are sensitive to temperature.  The chip is
probably tested at higher than normal operating temperature according
to the specs.  Some chips that just failed to make the 33MHz grade at
high temperature could actually run well with good ventilation.
 
Finally, if Intel has a huge order of 25MHz and have a huge stock of
33MHz, they would simply re-mark the chips as 25MHz and ship it.  This
is the most likely case as Intel seems to have controlled their
process to be able to have high yield of 33MHz.

My guess is that some vendors got wise to this and start pushing their
25MHz chips as 33MHz.  They'd most likely burn in the computer using
some software utilities for a couple of days.  And if nothing breaks,
it is sold as 33MHz.  Whatever the case, it is ethically wrong for
vendors to push 25MHz as 33MHz without the knowledge of their
customers.
 
............................................................................
. Kyle Hor                    .    /       / _   .  Email  khor@bnr.ca     .
. Bell-Northern Research Ltd. .   /__\  / / /_\  .  Phone  (613) 763-2488  .
. Ottawa, Ontario, Canada     .  / \  \/ /  \__  .  ESN          393-2488  .
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................  standard disclaimer, 2 cents opinion  ....................
.............  searching forever, for the perfect solution  ................