i purchased this exact card--it's still for sale at the link. the card is effortless to set up in dos, but it's giving all kinds of trouble in win9x & xp.
this link (probably mentioned above) has some additional info:
https://flaterco.com/kb/audio/ISA/index.html#OPTi930
he's right about the fm synth being loud and his kernel module parameters got the card running immediately in linux, but the info about the card manufacturer is wrong. when i downloaded the actual drivers for the btc 1817dw they were exclusively for the opti 82c931, not a 930/931 combo.
the nt drivers i located work for xp, but were a mess in dosbox which i assume has something to do with directsound. adjusting the mixer blocksize from 1024 to 4096 got the digital sound ungarbled in dosbox.
right now i'm trying to get the card working under win98se, which has actual drivers for the 82c930, but i can't get the onboard wavetable to work. the drivers i got from vogonsdrivers installs an opti930 sound system mpu-401 device (and corresponding midi mapper entry), but the device has a yellow exclamation mark in device manager that i can't resolve. i haven't reserved any irq/dma's in the bios config, but windows isn't reporting any resource conflicts (including the single memory & irq for the mpu-401 device). it's as if windows just doesn't see it