A common misconception is that test prep software is “just like the test“. Success with the national registry cognitive exam comes from having a good baseline knowledge that you can draw from to answer the questions.
There are several test prep software packages that are good at reinforcing baseline knowledge. medictests.com and JB navigate are both excellent.
The key to success with test prep is using the question’s answer rationale to build your knowledge base. Simply blasting through questions doesn’t do you any good.
One of the big changes with going to CAT exams vs standardized exams for everyone is that with the "standard" way of testing, you can teach to the test. How? You know what's on the test and therefore you can tailor what you present to the class. As a student, the information your instructor presents to you (often repeats certain items) closely mirrors the items on the test so it becomes easy to pick the "correct" answer from nearly rote memory. With adaptive testing, it's not possible to "teach to the test" because everyone gets a different test and that test customizes itself to the individual. What we're given in our primary/secondary education is the standardized test so the teachers tend to do the "teach to the test" method. That does "us" a disservice because then "we" don't often learn how to learn what we're presented with because the normal cues do not apply.
What does that mean? It's simple: we don't realize that we need a good foundational knowledge base until it's (sometimes) too late and fail the adaptive exam.
Now I get to echo NomadicMedic... you have to read the rationale for the answer for each question to start figuring out the underlying reason a given answer is correct or incorrect. As your knowledge base is built, you'll start seeing commonalities and you'll begin actually understanding the "why" and you'll be more likely able to correctly answer a question that you've never seen before simply because you understand what the question is looking for and why a given answer is the actual correct one to choose.
Just blasting through questions doesn't work except when you're dealing with a known question pool and therefore can just do lots of repetition/rote memory work... but you don't really learn anything that way.