No idea about demos, but late DOS games are highly compatible with PCI cards under DOS. They likely had access to more compatible drivers compared to the old days of Sierra and Lucasarts games 😀

In 1998 games were normally developed for Windows. Redguard was on of the last big DOS releases in late 1998 AFAIK.
PCI Sound Blaster real DOS emulation drivers require EMM386 to be loaded. Other then that I remember it usually works. FM/Midi Music quality is not so good.
This page is about PCI Sound Blaster emulation: http://www.it-he.org/sound.htm

The biggest problem if I recall correctly with the PCI soundblasters is that they have no MIDI/MPU interface that works in pure DOS mode. So you're out of luck if you have a SC55 unless you run the game in windowed mode within Win95/98.

Vortex 2 cards are great if you need SB Pro and a MPU401 interface under DOS.

Vortex 2 does XB Pro compat but not SB16? If I plug it in (PCI), can I run, say, a 1994 demo (years earlier) and specify SB Pro and have it work fully?

Thanks.

bp

Buy a few PCI cards and find out. Not sure why you mention demos, I would think many are programmed very close to hardware and might cause issues on PCI cards. Also many run well on a 386 but cause problems on faster PCs.

I mention demos as they are my primary concern.

bp