OPentium upgrade?

[George R. Gonzalez]

Hi, I have a Micron PC Millenium with a 200MHz Pentium chip.

As luck would have it, I NEED this PC to run some software that needs to
read the CPU clock time with the RDTSC instruction.

... Some early Pentium chips had a bug whereby you couldnt read the CPU
time with RDTSC if the CPU is in Virtual x86 mode.... which is what the
Win98 DOS box uses...... Guess What op system I need to run this software
on?

Yep!

So does anybody know of a Pentium plug-in compatible CPU that will just plug
in and give me a good working RDTSC?

Thanks,

George

[Ben Myers]

George,

I am unaware of this bug, but it would seem to me that Intel would have
documented it in a very precise manner in the errata which it issues for its
various processor chips. For example, the erratum could have been fixed in a
later stepping of the classic Pentium than the one in your computer. Or it may
not be in any of the Pentium MMX chips or later. In the absence of precise
information from Intel documents, I can only suggest a process of trial and
error, including possible replacement of either the system or the motherboard.
Have you tried the Intel web site for Pentium CPU specs and processor errata?
Also, the Dr. Dobbs Journal web site has a very good directory of documents
related to Intel processors.

Starting with the most simple possibilities, which motherboard is in your
system? If it is a Micronics M55Hi with a voltage regulator socket next to the
processor socket, you could install a suitable voltage regulator and use either
a Pentium MMX or an AMD K6-2 processor. (As a side comment, AMD, Cyrix, and
Centaur somwhat slavishly cloned Intel Socket 7 chips, and may well have cloned
the same erratum. Cyrix Socket 7 CPUs ran too hot to be worth a darn, so don't
even consider them.)

I have a selection of MMX processors here, as well as a couple of Centaur and
AMD chips that may fill the bill. I also have voltage regulators which fit the
M55Hi and comparable boards, allowing use of MMX and AMD CPUs.

You might be able to drop another newer motherboard into the Micron case,
because Micron used fairly standard ATX motherboards. However, the Micron cases
use a hard-to-find shape of I/O shield in the back to cover the ATX motherboard
external connectors.

On balance, it may be better to simply buy another used system, once you have
ascertained exactly which Intel CPUs are do not have the erratum that is giving
you trouble... Ben Myers

[Gary Tait]

On Fri, 09 Jan 2004 15:18:10 GMT, ben_...@charter.net (Ben Myers)
wrote:

>You might be able to drop another newer motherboard into the Micron case,
>because Micron used fairly standard ATX motherboards. However, the Micron cases
>use a hard-to-find shape of I/O shield in the back to cover the ATX motherboard
>external connectors.

The one on my MME (Anchorage Mobo, Palo Alto case), uses a standard
ATX backplate, except one of the DE connector holes wasn't punched
out. (it seems that the Anchorage Mobo was intended to have on board
video, with the VGA connector where COM2 would be, and COM2 on a slot
plate and ribbon). YOu can replace the plate with one that comes with
the Mobo (or at least should come with it, the one for my Athlon
system never, fortunately is uses the ame configuration as the stock
plate for my case)