It stands for Audio/Modem Riser. Basically, there are small cards you can put in that slot that act as a modem and sound card. They are really hard to find, though. I don't know anyone personally who actually has an AMR card, although I know plenty of people who have AMR slots.
Apple? Macintosh? What are these strange words you speak?
they're also getting replaced by cnr slots. These look like pci slots put on backwards. they act as only interfaces and make the cpu do all the actual work. I don't see th point of putting these things on performance mobos. Ehey should instead put in an extra pci slot.
<font color=red><i>Tomorrow I will live, the fool does say
today itself's too late; the wise lived yesterday
or 1 old ISA slot (stil have some ISA stuff)
AMR = Audio Modem Riser
CNR = Communications/Network Riser
IMO, and from what I've read:
1) cheap and cheerful ways of adding audio/modem/network
capabilities via software on the mobo.
2) useless as hell, since you can't find AMR/CNR devices
commercially; they're more for OEM guys upstream.