What happens if you format and fdisk the HDD on another rig? I used to do this all the time as it was a timesaver and I could pre-copy some files to the formatted harddrive so I didn't have to resort to other ways (like using ZIP disks or flash drives..or even floppy disks 😁)

Some hdds that I tried actually had an installation of windows on them.

Real men use the network to boot and setup stuff 🤣 (though all my 3com cards with a boot rom are used in systems, so I can't do that with a test rig. Speaking of network boot I think I should translate my tutorial video on how to create an image of a boot disk that allows you to access to a shared folder)

83.3mhz fsb required by cyrix?? I think that is way too high and it should probably be 75mhz fsb which is still fairly high for an intel chipset and NOT officially supported.
I think the later cyrix's had higher fsb settings and were really for ss7 boards.

Start with an official fsb of 66mhz and go from there....

Edit: Or are you running the mmx@3x66 now?

I'm running the 6x86MX ... but in fact I don't really know at what speed it is running.

Though like I said, if it was running at 83.3MHz fsb back then, it might have hurted a little bit the chipset. But at least the board is still usable if you take an IDE controller card, so it's not a huge deal even though I would have liked to not having to use it.

Deksor wrote:

I'm running the 6x86MX ... but in fact I don't really know at what speed it is running.

Though like I said, if it was running at 83.3MHz fsb back then, it might have hurted a little bit the chipset. But at least the board is still usable if you take an IDE controller card, so it's not a huge deal even though I would have liked to not having to use it.

There are many ways to tell the speed of CPU and FSB. The most direct way is by checking the jumper settings.
You can verify the partition info by using debug. Are you using DMA33 HDDs? You may try limiting the IDE ports to PIO only and see if it solves the problem.