In my opinion it's probably not worth the effort to get any PCI sound card working for DOS games in a 100MHz box. It'd be better to pay $20 for an decent (but old) ISA sound card.
As far as I know, the Audigy cards used hacked Ensoniq drivers for DOS support, as Creative bought out Ensoniq and used their PCI technology as the basis for the SB Live and Audigy series of cards. The Ensoniq (and thus Creative) DOS drivers use a software MIDI synthesizer that eats EMS memory (and thus it also won't work with games that have problems with EMS or the overhead required to use it) and uses mediocre-quality sound samples in an Ensoniq-proprietary ECW file format. The available ECW sample sets are only 2, 4, and 8MB.
They also have no on-board OPL chip. Instead, the drivers perform some kind of really awful-sounding emulation. Of course, most games can use General MIDI instead, but keep it in mind for the few that only support OPL.