For some reason iTunes will download a movie faster over wifi than with ethernet on my home network. When I do a speed test the ethernet connection appears to be a few mbps faster though... Why would it download slower on ethernet? (I turn wifi off when using ethernet via the thunderbolt adapter)
I know what your trying to ask here. When you do you speed test are you downloading the movie at the same time? If yes then the mbps will consistently change so when your over wifi and when your switching back to ethernet. If your were not downloading a movie when doing the speed test there is the difference already, when toe downloading something it using more data that means if more people are using the Internet as well then it will consistently change again.
To put it into a perspective, image your router has 20 (whatever of 20). Your wife logs on 20 goes to her then you log on splits 10 & 10 then you have let's say your friend over now it's uneven so your each getting 6.6 from the router. You see how it keeps getting smaller so there are so many factors that play in to make it better with Ethernet or better wirelessly.