Are there any particular circumstance where it takes 10-15% of one CPU for you or is it whenever there is sound playing? I just checked mine while playing music on YouTube and it bounces between 4.0 and 4.8%
Whenever there is sound playing or recording. I think it was lower than 10-15% on my most recent desktop, so maybe 4-5% makes sense if your computer is powerful. (While I fully appreciate that it is a very minor annoyance, 5% still frustrates me because PulseAudio added no value to me. I also understand that it added features very useful to other people.)