I'm talking about the free, 3-block practice exam provided by the NBME for Step 2 CK, not the paid self-assessments. I'm doing USMLEWorld and getting about a 60% average, so I'm petrified at the prospect of taking the exam this week. But yesterday I did the 3 NBME practice blocks and averaged 90%. Now I don't know what to think! Can anyone who did the NBME practice exam compare it to the real thing and/or to the paid Self-Assessments in terms of difficulty?