Mind you, the only new Ram's (2013) I have been in were both just idling, did not drive either one as I was just kicking tires so to speak for curiosity.
Both 6.7L Cummins diesels. Both had the doors shut, as engine loudness was one item I wanted to check out. Memory fades, but believe both were Laramie packages, I personally would be interested in the Laramie Longhorn.
Very quiet both vehicles. BUT, both to me seemed slightly louder to me than my current vehicle does under the same conditions. At idle, doors shut, not moving.
That said, this could also be a result of comparing the accepted, normal noise I am used to with my V-8 style Ford diesel to the surely somewhat different, but new to me, noise a new I-6 Cummins makes.
For sure, there is not a lot of difference between the two, but there was enough that I did notice it.
If one would want to get technical with a sound decibel meter, I would be willing to guess there was not a big numerical difference. Just more of a different sound than a different noise level.