Augmented reality (AR) technologies can overlay digital information onto the real world. This makes them well suited for decision support by providing contextually-relevant information to decision-makers. However, processing large amounts of information simultaneously, particularly in time-pressured conditions, can result in poor decision-making due to excess cognitive load. This paper presents the results of an exploratory study investigating the effects of AR on cognitive load. A within-subjects experiment was conducted where participants were asked to complete a variable-sized bin packing task with and without the assistance of an augmented reality decision support system (AR DSS). Semi-structured interviews were conducted to elicit perceptions about the ease of the task with and without the AR DSS. This was supplemented by collecting quantitative data to investigate if any changes in perceived ease of the task translated into changes in task performance. The qualitative data suggests that the presence of the AR DSS made the task feel easier to participants; however, there was only a statistically insignificant increase in mean task performance. Analysing the data at the individual level does not provide evidence of a translation of increased perceived ease to increased task performance.