Although there is some overlap b/w basic science and clinical years, people often do better in one over the other. Some people just cannot remember all of these stupid little details that have absolutely no bearing on patient care, treatment, or diagnosis. Others can do that easily, but have a hard time presenting to attendings or are uncomfortable /awkward doing a full H/P or dealing with certain types of patients (elderly, cancer, etc). Different people will shine in different things, and they are not necessarily related. Remember, patients never present with "Hi, I'm a 48 yo white female with a history of hypertension and diabetes presenting with crushing substernal chest pain, diaphoresis, and shortness of breath for the past 4 hours." Depending on the case, it can be really tough to put it all together and certain people can do this much better than others. Much different than exams, which kind of guide you towards the right answer (if you're taking a path exam on skin and GI, you know you'll be seeing path questions regarding skin and GI).
Also remember that in med school, you will not use about 30-40% of the information you actually learn - literally, gone as soon as you start year 3. Much of it is just not clinically relevent and no one really cares if you know it or not. Residency programs generally could care less if you know the biochemical pathways of gluconeogenesis or the target gene of follicular lymphoma. Conversely, you had better know what drugs are indicated (and contraindicated) for your patient's symptoms/disease as well as the top three most common and/or most deadly diagnoses for their signs and symptoms. And you had better show that you know everything about your patient's presentation (labs, images, history, overnight changes, etc) and be able to do one hell of a workup. Think about it - if you're a hospital, do you want someone who knows obscure facts or has shown that he/she can handle the actual practice of medicine?
