Tyan MP revisions

[EazyduzIt]

I know this board is getting on a bit, but it is currently the cheapest dual AMD solution, so I thought this might be of interest to people considering this motherboard. This is taken off the 2cpu forums: link

I don't have specifics beyond the clock, but here is a Tyan Usenet post that explains revisions and why they happen. The following is not from me, and credit is given at the bottom through the original author's sig.

------------------------------------------------------------------------------------

Here is a recap of a post I made a while back. There is a lot of stuff
that isn't really necessary to know, but read it anyway:

The way Tyan mark their motherboards you've got to either flip it on
it's back or have access to the table below in order to know what
version you've got.

1: COT
2: OOY
3: MOA
4: PON
5: UOT
6: TOY
7: EOA
8: RON

On the Timer MP the version code is silk-screened in the corner right
next to the DIMM4 memory slot. On the board I've got in front of me
right now it says: "01OOYB"

Checking the table above I find "OOY" and can see that this is a
Rev:02 motherboard.

If I flip the motherboard on its back i can se the revision number
stamped next to where the last 32-bit PCI socket is located. It's the
number within a rectangle that's the revision number.

Now what's that revision letter everybody is talking about?

Ok here I go again...

The revision number is used to identify the PCB (Printed Circuit
Board) version, while the letter is what is known as a ECN (Engineer
Change Notice) identifier.

Motherboards are (almost) never created perfect. Each time a problem
is identified Tyan tries to solve it by if changing the BIOS, changing
/ adding components on the motherboard or by changing the PCB of the
motherboard.

Changing the BIOS is cheap. It can be used to solve problems with
motherboards already in the hands of users. That's why we see new
BIOS'es every now and then.

But it's not always possible to solve a problem just by tweaking the
BIOS. In those cases Tyan tries to solve the problem by adding
components to the motherboard during manufacturing. This is more
expensive than issuing a new BIOS. And motherboards that have been
sold will have to be returned to the factory to be reworked. Expensive
stuff.
Every time such a change is made a new ECN is created. These are
identified by the use of both PCB version (02) and the ECN letter (A)
to identify what revision of PCB is affected by this ECN.

When the reworks stack up, there is a really serious problem that
can't be solved efficiently by either of the methods described above,
or some components are getting hard to get, that's when it's time for
a new Revision. Changing the PCB is quite expensive. They have to
reprogram the robots in the factory to accommodate a new layout. The
design and trace layout of the new PCB has to be tested. And even then
there is always the chance that new bugs may be introduced with the
new PCB.
A change of PCB revision is not something that's done lightly.

A motherboard usually goes through at least three PCB revisions, but
up to five isn't unusual. The first revision isn't usually made
available to the public. The second revision may suffer the same fate
as the first, but more commonly this is the first that's shipped to
end users. A relatively immature technological platform such as the
AMD 760MP usually has a few quirks that it takes some time to work
out.

If the third revision PCB for the Tiger MP is just around the corner
it probably means one of two things. Either Tyan has identified some
incompatibilities that they have been able to resolve with a new PCB
layout, or they have been able to simplify the motherboard so it's
cheaper to manufacture. In either case it will eventually be good for
the end users. The one thing I hope for is better memory
compatibility. It's something that would really be welcomed by most
who use this motherboard.

Regards,
B.Slisk