Sound turbocharger or power steering ?

Hello all, I have the following question… every one of you knows the sound that gives the power steering at a strong impact of itself. In about this sound I also hear more often, if I just go straight out, idR but then, when the vehicle has warmed up… it is not very loud, but I hear it. I thought it was the power steering at first, but since I also hear that when driving straight out, I actually excluded it again. s comes from the turbocharger, I imagine that it is a bit more interesting when I was on the highway…has someone had that already or an idea or is that possibly also normal? Thank you already now for your feedback & nice greetings eagle111