I didn't realize how much of the sets in Game of Thrones are done on computer until I watched a making-of for one of the seasons. Even knowing, I can't tell when watching.
Ex Machina had huge amounts of effects. CGI is a case of "When you do things right, people won't be sure you've done anything at all."
One of the three principle characters had a transparent body through much of the film. It amazes me people could think it was light on GGI, or not be sure anything had been done.
But it had a tiny ($15m) budget, which is opposite of what this thread is saying is possible (lots of CG, not much money).