Recently switched over to GC (Syntec 0w30) in my '08 Ram 4.7, and have noticed a few improvements over the previous oils used (M1 0w20 & PP 5w20). Cold valvetrain clatter is still there, as it was with M1 & PP...must be an inherent characteristic of this engine. But when warm, the valvetrain is considerably quieter with GC and the engine does idle a bit smoother.
OCI with the M1 was 7500 mi, and 6k with the PP...am thinking will run the GC for 10k miles, with a filter change & topoff at 5k.