Default [Q] High CPU usage when using Bluetooth for playing music

I've never used Bluetooth before, but recently I tried pairing with a car's Bluetooth system, for playing music wirelessly through the car's audio system.

Setup was easy and it worked very well, but it seemed to me like the phone became quite laggy and it even had a hang at one point.

How does bluetooth for music work for you? Do you have high CPU usage too? Can the system in the car have any influence on my phone?

Running Samsung software 4.2.2 build UBNB1 (Germany), rooted and most Samsung junk removed.