Haha I'm not quite that special, I never took a practice exam cold. I doubt that most people who scored tops on the real test would've done so without any review, since senior physics majors just woudn't remember everything about stuff like lens systems and thermo problems do be able to do them quickly on test day. Also, many of us haven't had any exposure to certain topics. For instance, I had zero knowledge of stat mech, and very little quantum/solid state/AC electronics, so I had to learn the basics of those things or I would've missed a lot more questions.
One thing all of you preppers should remember is that the practice problems are far
more helpful and instructive once you know most of the material on them... so don't try to take them too early just to see how high you score. I originally printed out the practice tests long before I started reviewing that summer and had looked at a few random problems here and there but I waited until I was done most of my review like a week or so before the test to go through all the problems. Most of my mistakes were from computation errors or missing a detail of the problem, not because I was unfamiliar with the topic, since I had already done my reviewing. I only "took" one test (8677 or 9277, forget which) start to finish and that's when I got the upper 900s score... I was mostly just checking to make sure my pace was ok... I knew I "could" solve nearly all the problems based on my success when I'd try random problems (though I often made silly errors)... but when I did that I wasn't timing myself at all, just taking my time and then looking up the answer. So I had to check my timing with an old test, but I still didn't consider that a prediction of what I'd get on the real test, especially since I had taken it in a half-assed manner in my bed with an AIM intermission and I had seen a few of the problems before etc, and most importantly because to me the tests seemed so drastically different from each other given the scoring. I found the 9677 test to be easy since there were a lot of conceptual problems that I'm good at and the very generous score scaling, and I think I could've easily gotten 990 on that, but for me I was very scared cuz I had an awful tiime with 0177 and wouldve bombed that one miserably if I had to take it for real, and since it was the most recent test and the one everyone says their test is similar to, I was very nervous