A study to assess the effect of SeeIT 3D, a software visualization tool is presented. Six different tasks in three different task categories are assessed in the context of a large open-source system. Ninety-seven subjects were recruited from three different universities to participate in the study. Two methods of data collection: traditional questionnaires and an eye-tracker were used. The main goal was to determine the impact and added benefit of SeeIT 3D while performing typical software tasks within the Eclipse IDE. Results indicate that SeeIT 3D performs significantly better in one task category namely overview tasks but takes significantly longer when completing bug fixing tasks. Scores obtained by the subjects in the SeeIT 3D group are 13% better and 45% faster for overview tasks.