Okay, I found my old docs on this motherboard. It’s basically the same as a “PM486PU-S3”
http://www.elhvb.com/webhq/models/486pci/pm486pu.html

I have an AMD5x86-133 P75 CPU installed.
It is not officially supported but I set it up with AMD486dx4-100 with WB settings.
I have it running at 3.45v and 40mhz.
So I am trying to achieve 4x40mhz. But it is not working.
It shows up at 120mhz.
I do not see a clock multiplier setting.

Can someone check this manual and tell me how to properly set this up as AMD5x86@160mhz. ?
http://www.elhvb.com/webhq/models/486pci/pm486pu.txt.html

you answered your own question its not properly supported so its not showing as 160 but it is running at 160 use a speed utility to verify

So is it okay to use AMD486dx4 ( WB ) settings at 40mhz ?
Test show it is running at 3 x 40mhz.
123mhz.

How can I set the multiplier to 4 x 40mhz ?
I don’t see any settings in manual.

If the "AM486DX4(WB)" CPU selection isn't giving you a multiplier of 4x,then try the "AM486DX2" CPU selection.
However, you might then only get write thru support

CPU settings for AMD486dx, AMD486dx2, and AMDdx4 are the same ?
Except for these AMD settings.
The changes are in .mhz and voltage.
There is no multiplier setting listed.

Unfortunately, this motherboard's jumper settings is the same for 486DX2 & 486DX4 CPU's, which is a bit odd.
Normally, if you jumper a motherboard for a 486DX2, then the AMD5x86 CPU's internal multiplier will automatically use the 4x multiplier.
However, in this case, it seems you're stuck with a 3x multiplier, since it's interpreting your CPU as a 486DX4.

So i think I will put these setting back for a 486dx4@100mhz. 3.3v.

3 x 33.3mhz. At 3.3volts for 100mhz.

What do you think?
Should I keep the AMD5x86-133 @ 100mhz or put an Intel 486dx4-100 into the motherboard ?

Intel486dx33 wrote:

So i think I will put these setting back for a 486dx4@100mhz. 3.3v. […]
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So i think I will put these setting back for a 486dx4@100mhz. 3.3v.

3 x 33.3mhz. At 3.3volts for 100mhz.

What do you think?
Should I keep the AMD5x86-133 @ 100mhz or put an Intel 486dx4-100 into the motherboard ?

Perhaps just benchmark both CPU's.
Provided that your motherboard properly supports the L1 write back cache scheme of the AMD CPU (I presume you are jumpering it for the "AM486DX4(WB)" CPU), it might run slightly faster than the Intel 486DX4-100.
I would jumper the AMD CPU for the correct voltage as per the specifications (which is 3.45V) but, it seems on this motherboard, all the jumpers below 5V are the same.

However, I noticed that you have another thread about your LS-486E motherboard. Since the AMD 5x86 is fully supported on that motherboard, just plug it in there and use the Intel 486DX4-100 on this motherboard.

PS: When jou jumpered the motherboard with the AMD 5x86 installed, was jumper J5's pins 2+3 closed or open?

J5 was closed as per instructions for am486dx4 (wb).

Intel486dx33 wrote:

J5 was closed as per instructions for am486dx4 (wb).

It should actually then apply a multiplier of 4x.
Try jumpering J5 with that jumper open (taking note what it reads your L1 cache scheme as (write thru or write back)) .
Also perform a benchmark (at the same frequency) with jumper J5 open and closed.

Okay, I am just going to put the intel 486dx4-100 in this motherboard.
is this CPU (WB) or not ?

Intel486dx33 wrote:

Okay, I am just going to put the intel 486dx4-100 in this motherboard.
is this CPU (WB) or not ?

Most Intel DX4-100 CPU's were of the write thru type.
Post a pic of the CPU.

I just used the default jumper settings for 80486dx4. I don’t know if this is for WB or not.
But it’s working okay now.