Running Windows 95 OSR2 on Pentium 4 hardware - booting error

TheBoyConor

Hi,

So many here will know i like old retro systems.

The latest just for fun project is a refurbishment of an old system I got off of Adverts.ie for €20 in Laois.
Specs are as follows:
MB: AOpen Mx 46-533GN w. SIS 651/962L chipset
CPU: Pentium 4, 3.4 Ghz
RAM: 256MB DDR 333Mhz
HDD: 80GB drive that I already had from a scrapped Dell.

My ultimate goal is to arrange a treble boot of 95, 98 and Me on this machine.


And now the problem I face that I hope someone here might be able to advise on is this.....
I have made a boot disk and installation ISO and have proceeded through the installation on a 2GB partition which I made using FDISK.exe on the boot disk. However, when I go to boot the OS the first time after installation I get an error saying "Windows protection error, you need to restart your computer" and rebooting doesn't help.
After some googling, it appears that Windows 95 has a limitation of a 2.1Ghz CPU or else it shíts itself and won't boot. There is a fix for this that uses another floppy image to patch the OS, which I have done.
That brings me forward to another error - HIMEM.sys corrupt or missing. I tried recopying this into the Windows directory from the boot disk but no joy.

So i was considering two other hardware mods to solve it:
1. Underclocking the CPU from 3.4Ghz down to sub 2.1Ghz to come in below the OS's limitation.
2. Purchasing a cheap P4 1.7Ghz CPU compatible with the chipset to give a hardware configuration more likely to satisfy the limitation.

i have tried looking for a Pentium II motherboard but they are so old they are a) scarce and b) very expensive.

Has anyone ever came across a the issue of the 2.1Ghz limit and the HIMEM.sys error and if so how did you get around it?
And any other suggestions or ideas are more than welcome.

the_syco

Considering it only needed 4MB of RAM, 256MB may be too much, LoL.

https://msfn.org/board/topic/141402-windows-95-21ghz-cpu-limit-broken/?do=findComment&comment=906670

DEVICE=A:\DOS\HIMEMX.EXE /testmem:off

So the above would probably skirt around that issue, as HIMEM is a memory thing?

TheBoyConor

It is OK, it turned out to be a thing where Win95 can't run on a CPU faster than 350MHz. I found a fix that can be installed after Windows 95 that removed this limitation.

I got the OS going fine but the motherboard since seems to have gone duff as nothing will boot on it. I'm due to get another MB soon.