There could really be a slight difference connecting machines when the other one is on a wireless network while the other one is on wired. Though both network comes from the same router, there might be a split second delay when it passes the switch from wired side and the wireless side of the network. Plus the fact that most wireless access points today is still using the traditional way of broadcasting, it broadcasts the data in all directions.
But there's actually a better way of broadcasting on wireless network. It's called "Beamforming." With beamforming, the router determines where y