I really saw no correlation.
I am probably in the 'top 40%' (in quotes because who would claim that? haha) I'm above the half way mark, maybe above 60%, but definitely not in the top 20%.
My mindset through med school has been - don't become the stereotype. I studied like I studied in undergrad - go to class, listen, learn, but I really don't study daily. I would start studying for exam week about 2 weeks before the block (we take exams 4 times a year - its a 2 week block of all our exams). So 2 weeks before that block, I'd start my studying for the exams. My grades range from H in some things, HP is most, and the occasional P (many of my HPs were times when I score low 90s on an exam but our class averages were always pretty impressive and they stuck to the SD-grade distribution). I might be underestimating my position in my class, but its a good school and a competitive bunch so I'll stick by my initial guess.
I took my same approach to step 1 - I had faith that i had learned a lot during my first 2 years, so I took 2 weeks off after my final exams in early May then started to prepare for Step 1 - M - F doing FA and Questions, no studying on weekends, and going out w/ my fiance whenever we wanted to (except the week of the test). This went for about 3 weeks, and I took the week off before the exam since I took the exam on a Friday.
Result: 250/99 - A score that I think puts me much further up in my class than you would have expected from my performance throughout the first two years (relative to my peers). So I say there is no correlation because I didn't drastically change my study techniques from my performance throughout med school.
My advice: Trust yourself. I won't say all med schools, but the questions professors ask you throughout the years aren't always questions to best prepare you to be a good doctor but more a way to see who they can trick so that they can get some sort of differentiation in grades among a class of 180 really smart people.
You know how you prepare. Don't let people tell you that you aren't doing enough/judging you - and know that just be being eligible to take Step 1, you're so much more likely to pass Step 1 than fail it (I know we aren't aiming for just pass/fail but see next advice point)
One thing I truly believe is don't get some score in your head that you want or need - prepare how you need to, do questions, take your practice exams but don't get discouraged by calculators or start 'expecting' certain scores because a practice test says you will get so and so. The test is a marathon and the stress alone of pass/fail (even for you geniuses who scored 288), even if you know with almost full certainty that you won't fail because you are so well prepared is enough to take someone who had the knowledge base to get a 260 down to a 210. If you go in thinking "Man I need a 250 or else I am screwed" you are just asking to get a hard first block that completely destroys your confidence and ruins you for the rest of the exam.
Those last few parts had nothing to do with correlation. Sorry! haha