Do whatever works best for you. No one knows that but yourself, and you may have to experiment.
Personally, the best study method I ever saw was:
1) Take notes during lecture
2) Review notes immediately following lecture
3) Take a break
4) Complete all assignments that day so nothing builds up
This requires incredible self-discipline and motivation that I simply could not do personally, particularly not with the schedule I had during undergrad. I generally took notes in class and crammed for exams, but it worked out, though it doesn't in medical school (but you also have time devoted to study, rather than time-killing extracurricular nonsense).
Either way, taking 3 hours to transcribe a single lecture into a concept map sounds incredible excessive (FOR ME). Maybe you need to figure out what you're actually using and what you're not. Being successful all ends up coming down to being efficient, and if your study habits aren't efficient you're losing a huge amount of your life's return on investment.