Every time I listen to music on iTunes or VLC, I notice that the process coreaudiod causes an unusually high CPU usage (5% or more).
Are you having the same issue? What's the reason for such a high CPU usage?
Recent OS X updates have not changed this observation. Restarting (or killing the process so it respawns) doesn't fix the problem. After a couple of seconds, CPU usage of coreaudiod goes above 5% again.
It's important to note that using line out makes the problem go away and coreaudiod's CPU usage goes down to 1%-2%.