PWS 500 a/u overclocking & jumpers?

["Jon Norstog" <jnorstog shoshonebannocktribes com>]

To the list:

I recently got a second PWS500a/u, this one a GL model with the USB
ports. What was I thinking! Anyway, I'd heard that the Miatas can be
overclocked and decided to try it with the older machine.

I got a list of jumper settings posted on comp.sys.dec August 15, 2002
by Marco Nuessgen.  I eBayed a 533mhz cpu as a spare, it arrived yesterday
so I decided to try O'clocking it.

I put in the 533 (it came with a PC 164 heat sink) with the Miata heat
sink and the little strip ov silver heat transfewr film from the 500 mhz
CPU,
and set the jumpers to what was supposed to be 600 mhz.

The setting I used is below:

00000101 	1 being up and 0 being down, relative to the bottom of the
		MoBo.

Show Config indicated the CPU was running at 533.  I tried booting
Linux, the kernel got lost looking for the PCI bus and gave up.  I took the
CPU
out. It was pretty warm, considering it had been running only a few minutes
under light load.  So I took the new CPU out for a look.

I noticed that the little silver heat transfer sheet, which had never
melted under the 500 cpu in 5 years of active use, had fused to the
new 533 CPU.

I put the old CPU in with its original heat sink.  It ran a lot cooler but
still
would only go 533.  I didn't bother trying to boot Linux or Tru64 (alhtough
I bet I
could've got Windows 2000 to come up off ARC.)


Marco's post showed the following jumper settings

433 01011001
500 01111001
600 00000101

does anyone know if these are right?  If so, are my CPUs somehow
internally limited for clock speed?

Unlike on a PC, changing the CPU frequency on the Miata seems to move
a lot of furniture around, changing some IRQs as well as PCI and memory
frequencies. Perhaps a successful overclock means some pretty serious
reworking
of my Linux & Tru64 OSes, maybe even a rip-out and re-install?

Well, has anyone else tried this?  How did it go?

Thanx

jn