🚀 go-pugleaf

In article <1109@watserv1.waterloo.edu> ssingh@watserv1.waterloo.edu ($anjay "lock-on" $ingh - Indy Studies) writes:
$But one machine was different in that it forces the SX to 20 Mhz. It was
$called a Citrus something or other. This was it's main distinguishing feature.
$It implies that one can tweak other boards to get this kind of performance.

   Not advised.

$1.) Does anyone know how to do this?

   Well, you don't just go in and plug in a faster crystal.  The various
glue chips have to be able to handle whatever speed you're running at, and
also the timing for the expansion bus may be derived from the main
crystal.  You want to keep the expansion bus running at 8 MHz since many
cards won't run any faster than this, and if it's run off the same clock
then you're out of luck.

   I've heard that microprocessors are actually supposed to be able to run
at up to 1.5x the rated clock speed.  This doesn't make much sense to me,
but that's what I've heard ... it may be wrong.  But pushing a 16 MHz
part to 20 MHz shouldn't be a problem, given that the rest of the design
was based on the higher speed.

$2.) Is it worth the risk with overheating the components?

   If you provide the box with adequate cooling, the parts don't get
hot enough to worry about ... this is what was done with the first few
33 MHz 386 machines, back when 25 MHz was the fastest chip available.

$3.) BTW, WHY does the componentry heat up?

   I think the heat is generated when a gate switches states, so by
increasing the clock rate 25%, you also increase the rate at which the
gates switch by 25% and increase the heat production similarly.  Of course,
this applies to the same chip run at two different speeds.  If you're
comparing two chips fabbed with different scales (e.g. a 1.0 micron
chip against a 1.5), even at the same speed they'll dissipate different
amounts of heat.
-- 
Stephen M. Dunn                               cs4g6ag@maccs.dcss.mcmaster.ca
          <std_disclaimer.h> = "\nI'm only an undergraduate!!!\n";
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               I Think I'm Going Bald - Caress of Steel, Rush