I've both Moto Z and OnePlus 3. Processor same except the former has 4GB RAM and the latter 6GB RAM. In terms of normal usage, nothing special but OP3 battery seems to drain faster when multitasking. App smoothness? Same. Launch time also same. Only problem is battery drain. That could explain why OP3 only has FHD display while MZ has 2K display.

So, conclusion? More RAM, higher battery drain.