For example
many of the cheaper onboard AC97 sound chipsets have no
hardware mixing and no hardware volume control - they rely on the
Windows kernel mixer. Since the equivalent technology on Linux is not
as mature we have problems. And since the crappiest hardware is
disproportionately affected, and requires the most work, many of the
issues don't get fixed.
I see what you are saying.
Today, most mobos contain onboard audio (like the Realtek ALC850, 650).
Are there any that don't?
Any other audio-centric hw gotchas that one should look out for when
choosing a mobo?
It doesn't really matter if the mobo comes with built in audio. You can usually set a
jumper or set the BIOS to disable it. You won't find many boards anymore that
don't have audio built in.