When I was a student I spent a lot of time in class writing down what was being said, and reading my notes later on, there's a lot of stuff I don't remember learning. When I look stuff up on Wikipedia because I'm curious, I don't think I remember less than when I was writing everything down.

Now I tend to only write down a very short summary of the most interesting/surprising bits, ideally with a diagram or silly drawing, but then I haven't been reading much textbooks recently. If I was back in "I nead to learn all this new information" mode, I'd probably do a mix of exercises, and Anki.