On 11 Apr 99, at 0:20, Sami Al_mohssen wrote:

> would someone explain to me the role of the multiplier jumper. all I
> know is that the motherboard use it to multiply with the bus speed
> jumper tp get the cpu speed.
>
> i don't really understand how does it work. and why is it so
> important for the mother board to know the cpu speed since everything
> connected to the bus is going to run at a specific speed.

  You're correct in assuming that the multiplier circuitry is inside
the CPU "package".  But [except for some recent models...] you're
incorrect in assuming that this circuitry is hard-wired to a single
specific multiplication factor.  Instead, the circuitry is capable of
several different multiplication factors, and the chip's rating
constitutes a statement of the manufacturer of which combination of
multiplier setting and bus speed work reliably.
  The purpose of setting the multiplier jumpers isn't to tell the
motherboard what multiplier the CPU has; those jumpers connect directly
to pins on the CPU to tell the multiplier what factor to provide.  In
most cases, the CPU will run just fine (but slower) if a setting less
than its certified rating is selected, and if you're lucky, it may also
work faster at a higher setting.
  [This is one form of "overclocking", running a component beyond its
certified speed; (a) it may not work, (b) it will increase the amount
of heat produced, which can damage components, and (c) it will void the
warranty.  None of that discourages some people.]


David G

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