Research on how epistemic beliefs influence students' learning in different contexts is ambiguous. Given this, we have examined the relationships between students' scientific epistemic beliefs, their problem solving, and solutions in a constructionist computer-simulation in classical mechanics. The problem-solving process and performance of 19 tenth-grade students, with different scientific epistemic beliefs, were video recorded and inductively coded. Quantitative analysis revealed that different sets of epistemic beliefs were conducive to different aspects of students' problem-solving process and outcomes. Theoretically sophisticated beliefs were in general associated with logical strategies and high solution complexity. However, authority dependence was associated with high degree of adherence to instructions. Hence, there might not be a universal relationship between the theoretical sophistication of students' epistemic beliefs and quality of learning outcomes. We suggest that the conduciveness to desired outcomes is a better measure of sophistication than theoretical non-contextualized a priori assumptions.