For me, the biggest improvement is when using SETMUL. The P55C design has more parameters to toggle for throttling and more performance differentiation from those parameters.

You will need Win95 OSR 2 or later build with proper support for MMX, or you may encounter BSOD if software/games try to use it with OS knowing nothing how to handle it.

_UV_ wrote:

You will need Win95 OSR 2 or later build with proper support for MMX, or you may encounter BSOD if software/games try to use it with OS knowing nothing how to handle it.

I will be using windows 95 osr2 dual booted with dos 6.22/windows 3.11

I got my hands on penitum 200mhz mmx cpu and something is a little weird, my machine would not post with the correct jumpers (according to the manual)

However it does post and say it penitum mmx 200 with one jumper on single voltage (not dual voltage) and another jumper (again according to the manual) is on p54c std not p55c but it the only way it will post

Will I be OK leaving it like this

With some good cooling the mmx will run fine with 3,3v. But if that board is supposed to support the mmx I would try and sort out the jumpers first.

Some very early So7 boards were made with optional support for P55C, with place for the required VRM, and jumpers to go with it, but without the VRM itself. Does it look like there is VRM circuitry near the CPU socket linked to JP6? If not, it might explain why it doesn't work...

I don't see a vrm near jp 6, only a capacitor and a metal heatsink near bottom of mobo (well what looks like a heatsink)

Here is a pic of the section where there is heatsink

There are two transistors screwed in that heatsink which are there to regulate the CPU voltage. But as you can see, on the right there is a spot for a third one. I'm not sure if it's needed, but the circuit has been made for three transistors.

I am guessing even tho there is jumper for dual voltage, is no circuit for it, hence when the jumpers are set right according to manual for this cpu doesn't boot or post

Is a way to get the part for vrm to screw and solder into the third space on the heatsink or will it easier to get another socket 7 AT motherboard that has the circuit for dual voltage

Here is a pic of post screen with jumpers set for single voltage and p54c set (which is what my p133 was at), only jumpers that needed to be changed was the multiplier setting

I guess you could ask somebody that has this board what's the reference of the missing transistor ?

Maybe this ebay seller would help you : https://www.ebay.com/itm/A-Trend-ATC-1000-V-2 … m-/172146172367

If you have ok soldering skills, this should be easier to do than finding another socket 7 mobo for cheap.

By the way, I see you have 80MB of ram, but the i430VX chipset can't cache memory past 64MB

I did see that board on ebay and message the seller, if he would sell witout the ram and cpu but yeah could ask him what transistor is used there and see if possible to do

I do know that about the ram but I haven't noticed any performance difference at all

Well as long as you don't use more than 64MB of ram, you should be allright, but if anything gets over it, it will not be cached

Deksor wrote:

Well as long as you don't use more than 64MB of ram, you should be allright, but if anything gets over it, it will not be cached

i know and have it in mind

Now that I look closer, that third transistor might not be the only missing component : there's a missing IC with "U27" labeled on the PCB. According to the ebay seller's photos, it seems to be the same as U26 IC.

Soldering SMD is more tough than a normal component, but if you feel you can do it, there are tutorials to teach you how to do that with a normal soldering iron

OK prob easier to find another AT motherboard or same one with appropriate transistors already there (just need to see if sellers are willing to sell the mobo on their own)

i have found the same mobo as the current one in this build but it has the transistor and ic chip for dual voltage already there, so fingers crossed, the issues is solved

got the mobo (with appropriate parts already there) and over a month later working no problem

You can use the top part of the RAM as RAMDISK with XMSDSK utility.
In your case, it would be a 16MB ramdisk.
I have 256MB of ram in my MMX build, of which 192MB is allocated to a ramdisk.