What happens to network performance on Linux/Mac when you play audio?

I'm curious.  What happens to network performance on Linux/Mac when you play audio?  If there's no network performance throttling, does audio playback suffer?

According to Microsoft getting the balance right between multimedia and other intensive processes such as fast network transfers is tricky, so I'm curious to know if Linux and/or Mac suffer from the same issues as Windows Vista does, or have these problems been ironed out long ago?

I don't have the time right now to set up two Linux boxes with gigabit adaptors and I don't have two Macs (I can't remember off the top of my head which Macs come with gigabit Ethernet adaptors - I think that maybe most do) so I'm wondering if anyone else could try it out and report back to me.