Every engine/car is different. Mine which has a new engine has a noisy drivetrain, and is noisier when cold. I can stay off boost, stay below 4000 rpm, stay below 35mpd; and in cold weather have a knock reading of 40+. Just shifting gears at 100mph+ , I can have a reading 120+.
If a stay in 4th and make a run from 2500 to 7500, it might not go over 35 until I shift. My car is almost 10 years old and has been a dayly driver all this time with almost 90,000 miles. Except for the engine, the drivetrain is original. Same for all axles and bearings.
Have owned my FD since June 1992.