It depends a lot on driving conditions, cold starts, short trips, Engine characteristics, etc.
I dare say if you fill your engine with clean oil in Seattle and immediately drive all the way to Miami, then any engine with any oil with only highway miles will probably go 200,000 miles and look as clean inside as any engine run the same time on synthetics.
I think though, over very long periods of time....... a "conventional oil only" WILL have some deposits inside, how much, I can't say. I changed the oil in my 5.0 Explorer engine every 4,000-5,000 miles and used mostly conventional (I always added 1 quart synthetic) and when I tore it down at 183,000 miles it was still VERY clean inside.