Tyan Tomcat III Jumper Help needed

Hi,
I'm putting together a system with a Tyan Tomcat III motherboard that I
purchased new many years and never got around to using. I'm trying to
install a P233 MMX chip on it, but set at the max speed of the board,
which is 200 Mhz. max. I think it should be possible to rate the chip
lower than what it's mf'd for, if I remember. The board is the
S1563S-512.

I could use help with some of the jumpers for the CPU Voltage Regulator
Settings. The manual (page 12) (available here:
ftp://ftp.tyan.com/manuals/m_s1563_100.pdf). The manual is wrong on the
top of that page where they list Jumpers 61-65 (found it on the Tyan
site) Jumpers 60-62 are really 37, 38 and 39. Jumpers 63-65 are really
42, 43 and 44. Now, they say that the rest of the chart is correct and I
assume that I should follow the jumpering instructions under the "2.85v"
column, since the back of the chip says "2.8v" or so, and the Intel
website lists the core voltage for that chip as 2.7-2.9v. That's all
easy enough. That shows how to set jumpers 40-44 and 52-54. That's
easy too. Now, what confuses me is that the other possible jumper
setting is for P54C (Pentium) & Cyrix, which isn't my chip. However,
they list instructions for jumpering 40-44 and 52-54, just like with my
chip, BUT they list the additional jumpers 37, 38, and 39. Now what do
I do with those if I'm using the MMX chip, as they don't show any
instructions for that.?

Next and last question. There are jumper settings for "DRAM Voltage
Setting". You have a choice of 5v (default) or 3.3v. How do I know
which to chose and which would I chose to set it for? I assume Default,
but I don't want to make any assumptions and find out that I'm wrong
later. They say that it can cause damage if set incorrectly.

Thanks for any help!

Danny

 

As long I remember, P233MHz need same jumper settings as P100,
EXCEPT voltage. Core voltage must be 2.8V and I/O voltage 3.3V.

Use default, because mainly there was only 5V memory in production,
but if you see SIMM-s with 3.3V-label, you must use 3.3V and do
not mix them with 5V memory modules.
We tired to run 5V memory with 3.3V - generally computer runs well
1 year or so, after that memory problems started. We turn voltage back
to 5V and computer work normally again.

Tarmo