Individual differences in cognitive performance depend on age, skill, and type of task. Nonetheless, whether performance is measured with accuracy (ACC) or with the trade-off between responding speed and accuracy (SAT) could render subtle different relationships. Age and skill might associate more strongly with SAT performance in reasoning tasks, whereas they might relate more similarly with either ACC or SAT in knowledge tasks. These expectations were evaluated here with data from the cognitively taxing domain of chess (n = 259). Age was associated more strongly with the SAT than with the ACC measures in reasoning tasks. In contrast, skill related more robustly with the ACC than with the SAT measures in knowledge tasks. The main findings suggest that the associations of age and skill with performance vary depending on the type of task, but also on whether considering accuracy or speed-accuracy measures of cognitive performance.