crumpton69@googlemail.com wrote:

> Does anyone know if the various speed CPU modules are interchangeable
> between 800CS/CT machines, to facilitate upgrading?

IIRC these machines used MMC-1 CPU modules. (About the size of a
playing card, and they have two connectors on the bottom that look
rather like miniature Centronics connectors. There is a very
similar-looking but totally incompatible MMC-2 card which has a single
connector with several rows of pins).

I think you can go up to 266MHz Pentium MMX on this machine. The
regulator is on the CPU card, so there is no need to futz with settings
on the mainboard.

zwsdotcom@gmail.com wrote:
>
> IIRC these machines used MMC-1 CPU modules. (About the size of a
> playing card, and they have two connectors on the bottom that look
> rather like miniature Centronics connectors.

Really?
Can anyone confirm this... would be nice, but somehow I imagined the
OB800 would use proprietary modules!

> I think you can go up to 266MHz Pentium MMX on this machine. The
> regulator is on the CPU card, so there is no need to futz with settings
> on the mainboard.

That's good news about the voltage reg.
Has anyone out there actually upgraded to above a 166MMX ??
If so, then *please* share! :-)

- Mark.

crumpton69@googlemail.com wrote:

> > IIRC these machines used MMC-1 CPU modules. (About the size of a
>
> Really?
> Can anyone confirm this... would be nice, but somehow I imagined the
> OB800 would use proprietary modules!

Open it. Then you'll be sure. I had a few old Omnibooks and I think
800CS and 800CT models amongst them. Looks like the fastest speed
available was 400MHz. But for reasons I forget - BIOS maybe - these
machines didn't run with anything faster than 200-and-something. 266 I
believe.

Here are some pictures:


> Has anyone out there actually upgraded to above a 166MMX ??

The units we had were 233s.