[citation][nom]dragonsqrrl[/nom]Didn't realize there was trouble with that, that's troubling. could you give more specifics about the problem?[/citation]
It's pretty well documented over on AVSForum and it's been brought up on ATI's own forums (although you'll learn that nobody related to the actual company cares enough to check the ATI forums).
Basically... If you set audio above 16 bit/92KHz or 24 bit/48KHz and play any unprotected (err, non-DRM, PCM) audio while you have windows set to a 5.1 configuration, the channels go crazy (front goes to back and L+R go to center, etc.) and you get massive (the kind that blows speakers) disortion. This problem is brought on anytime you open a new window or do any kind of multi-tasking. Slight distortion is also present on 2 channel, 24 bit/192KHz settings, but you don't get the channel problems.
I don't believe this is hardware related since 24 bit/192KHz audio works fine when you're playing a Blu-Ray and bitstreaming audio. Multi-channel PCM also work pretty well if you keep it below the above mentioned settings. Keep in mind that PCM works fine with the 4XXX series of video cards (I just upgraded and have tested it extensively with a 4870). This seems to be a problem related specifically to the way PAP is implemented in the new cards. ...on AVS, people seem to believe it's a problem with the Powerplay feature of the new 5XXX series. Who knows? Unfortunately the latest date on the driver is November 13 and they don't seem to be in a hurry to fix this issue.