Any human-computer interface imposes a certain level of cognitive load to the user task. Analogously, the task itself also imposes different levels of cognitive load. It is common sense in 3D user interfaces research that a higher number of degrees of freedom increases the interface cognitive load. If the cognitive load is significant, it might compromise the user performance and undermine the evaluation of user skills in a virtual environment. In this paper, we propose an assessment of two immersive VR interfaces with varying degrees of freedom in two VR tasks: risk perception and basic object selection. We examine the effectiveness of both interfaces in these two different tasks. Results show that the number of degrees of freedom does not significantly affect a basic selection task, but it affects risk perception task in an unexpected way.