Comment by aaronax
I'm pretty sure Aureal A3D was featured on my family's Compaq Presario 5150[0] back in 1998. The speakers were decently sized units mounted on the side of the 17" CRT and powered straight from the soundcard via 3.5mm plug which apparently was designed to output way more power than a standard headphone jack because it could go pretty loud.
A couple nifty demos were included. One was simply a bee buzzing in a circle, and it totally sounded like it was doing loops behind your head.
Old PC sound cards commonly had op-amps on their outputs that could produce a reasonably-clean Watt or two into a pair of 8-Ohm speakers.
Which doesn't sound like much, but 100 Watts is only 20dB louder than that if all else is the same, and most casual music listening happens with peaks that are in the realm of tiny fractions of a Watt.