Segfaults

[ME]

On Wed, 16 Feb 2000, Nancy Harrison wrote:
> Subject: Re: Segfaults
[chop]
> retailer's shop.  On that note, here is a question:
>    How do you tell if your chip is over-clocked?

There are people on this list which have worked for local PC
assemblers/shops which can offer better answers. If they have information
which contradicts mine, it is more likely they know what they are talking
about.

Until someone else can offer their professional opinion, I can offer a
simple answer. Written on the CPU is information which may tell you the
model, and chip manufacturer's tested/rated speed for the CPU.

Unfortunately, this information is often written under the heat-sinc, fan,
or heat-sinc-fan-combination. Many assemblers, vendors, and companies have
rules about removing this from the chip. They claim it will invalidate
your warantee. (Sweet for them eh?)

>    How can you set it to a lower speed, or can you?

This depends on many things. Some systems allow you to use BIOS/CMOS
software written on the motherboard to configure the speed. (These have
been rare in my limited experience.) Many more use DIP switches, or
jumpers to set the speeds of the motherboards and CPU.

Many motherboard vendors to not make it easy for you to set the clock
speeds of your motherboard and CPU, unless you have the manual.A small
number of vendors imprint their boards with an index to what the jumpers
are for, and how to configure them so you do not need their manual. The
boards have collections of jumpers noted with references like "J12, J13,
J14, J15, J16, J17, J18" and the manual for the motherboard explains what
jumpers should be set for what speeds of motherboard cycles, and what
jumpers should be set to tell the motherboard just how fast the CPU that
has been placed into the socket may be pushed. (The above example jumper
references are *examples* and are not likely to be the actual jumpers used
on your board.) 

The motherboard manual might say:
80MHz  motherboard J12-ON, J13-ON, J14-OFF
100MHz motherboard J12-ON, J13-ON, J14-ON
(And a few other speeds with jumper combinations)
then it might say:
Pentium     J15-ON, J16-ON
Pentium Pro J15-ON, J16-OFF
Cyrix       J15-OFF,J16-ON
AMD         J15-OFF,J16-OFF
And then maybe:
x2 CPU J17-ON, J18-OFF
x3 CPU J17-ON, J18-ON
x4 CPU J17-OFF,J18-ON
x5 CPU J17-OFF,J18-OFF

Then you bridge the jumpers for ON positions, and remove the jumpers, or
don't bridge the "J-whatever" pins for OFF to describe your hardware.

In this example, if you had a 100 MHz clock speed for the mother bus, and
told the motherboard that the CPU was rated for 5 times the speed of the
bus, then you are saying your CPU is rated for 500MHz operation. 

This above description is very general, and different motherboard
manufacturers have their own systems for configuring their boards.

Don't use the above made-up matrix, cause I made it up in my head, and
probably does not apply to any system on the market.
[chop]

-ME