“Question bank or practice exam?” has no single answer; which one carries the weight depends on how much time is left and how much of the topics you have finished. The framework below is a general approach; you can adapt it to your own pace.
Far from the exam: topics and question banks
While learning topics, solve that topic's question bank right after each topic. Applying what you learned to questions immediately improves retention. In this period the number of practice exams can be low; a few general exams a month show you where you stand.
As topics near completion: mixed questions
As topics are finished, move from single-topic tests to mixed tests. In the real exam questions are not ordered by topic; you have to notice which topic a question belongs to yourself.
Close to the exam: mostly practice exams
- Take one or two practice exams a week.
- After each exam review your wrongs and blanks.
- Add a short review and a few questions on any topic that comes out weak.
Which is more useful?
They cannot replace each other. A question bank measures your learning and practice, and a practice exam measures time management and your overall standing. If you only take practice exams and do not review your mistakes, or only do question banks and never work against the clock, you will fall short.
A small tip
Re-solve the questions you wrote in your mistake notebook at regular intervals. What matters is not how many questions you solve but that you do not repeat the same mistake.