I'll just throw out I've used Anki ever since I started it and haven't failed a knowledge test since I started doing it. Including passing my HAM test with only using Anki and the questions for 72 hours.
Using Anki for a 72-hour cram session is kind of missing the point though. For me, the main benefit of Anki is to escape the cram->forget cycle and learn things low-stress and for good.
I 100% agree that is the optimal way. But it can be useful to memorize 300 questions and answers in 72 hours if you have to.
Word of caution to other readers: Don't use Anki for cramming. Especially not if you didn't learn and understand the material before cramming.
Could you explain why that might not be a good thing to do, siva7?
I've used anki for over a decade and done that mistake several times. Anki is designed to reinforce knowledge you've already learned, not to introduce new information. The cards shown in a SRS alogrithm don't follow an order which makes it suited from a pedagogic POV for acquiring new knowledge. Cramming tends to be done when knowledge hasn't been yet learned or understood sufficiently.