This reminds me of my father's old 386DX40 PC.
It had a Mitsumi LU005 which Win95 had got no drivers for.
Thus, it was required to fall back to the DOS CD-ROM driver.

Gratefuly, that one worked under Windows, too.
As far as I remember, loading MSCDEX wasn't required, though.
Win95 had its own native CD-ROM extension built-in.

However, loading MSCDEX was still possible, even though it decreased performance.
Unfortunately, Win95's built-in MSCDEX counterpart nolonger supported CD-i (MSCDEX did).

Jo22 wrote:

This reminds me of my father's old 386DX40 PC.
It had a Mitsumi LU005 which Win95 had got no drivers for.
...

I think experiences such as what you described above is what feeds the modern (mis)conception that legacy DOS drivers are harmful to Win9x performance.

I believe it may have been very true in Win95 timeframe, perhaps even early Win98; however, I've been using Win98 SE for nearly 2 decades now and as far as I can tell, it has no problems overriding the legacy DOS drivers and loading its own 32-bit drivers. I found absolutely no indication of decreased performance due to CD-ROM/Mouse drivers being loaded, nor indication that Windows is using any of them (although, of course MEM still shows them to be in memory).

Sorry about that. 😢 Unfortunately, I originally grew up with pre-586 hardware mainly (even pre-486 to be precise) so that was my experience.
If my memory serves me well, the 586 era roughly was about the time when we (at home) stopped mixing legacy and current hardware.
Comming from the 286 days, I often skipped using things like SmartDrive, EMM386 and such, because they were either not
compatible or taking up precious memory (I even used English keyboard layout at one time, along with Codepage 473).
And on that old 386 or a Pentium 75, using a cacheless MSCDEX vs the built-in CD-ROM extension of Win95 was noticeable, if memory serves.
Perhaps not extremely, but opening a folder on a CD-ROM with MSCDEX being loaded was a bit slower
(you could see the icons being loaded one after another).

Nothing to apologize for; I do not question your story. 😀

You can find discussions about these kind of problems, for example here:
https://www.techrepublic.com/article/solve-ms … eshooting-tips/

I think I may have seen such messages in the past, but I have two computers running Win98 SE, with the basic DOS drivers loaded, and I don't see any of these messages; furthermore the Device Manager shows the Windows VXD drivers being properly loaded, DMA is available for CD-ROM, etc. So I really don't know where the problem can be and how I would be able to determine it. I've tried booting with/without loading DOS drivers, and found no different in the way Windows behaves...