For high test grades, you need to do both. Associative memory is much more reliable than rote, so it's important to use it as much as possible. Organizing the material not only helps you understand the material, but it helps you recall facts, ideas, events, and logical arguments. If you have a really good memory, you will forget at least one-fourth of what you learn by the end of the day you learn it.
Organized information is easier to find.
Use your body. Use your brain. Work with your memory, not against it. This is easier when you use the other principles to store information. Organize It 1.