Hello, I'm currently at the graduated undergrad level concerning physics and I'm considering eventually doing a PhD in America. Usually this requires a Physics GRE test, which is meant to check whether you have absorbed the necessary knowledge from the undergraduate studies. Good. Well, I checked a practice test of Physics GRE and conceptually it all seems pretty straight forward, not hard, but what strikes me is that it requires a lot of speedy calculations, which I don't feel very comfortable with. Why does the emphasis seem to be on being able to calculate things quickly? Sure, you should be able to calculate simple things rather quickly without much effort, but still, the time allotted combined with the number of questions and the type of questions seems to imply you have to be quite quick on all of them. Isn't it more important to understand what's going on and know what you're doing than quickly producing the quantitive result? I don't want to be as arrogant as to argue with the test, I'm sure lots of people responsible for the test have thought over what they wanted to poll with the test, I just wanted to check whether my impression is correct and why the emphasis lies where it does.