Autism spectrum disorders (ASD) are characterised by a unique pattern of preserved abilities and deficits within and across cognitive domains. The Complex Information Processing Theory proposes this pattern reflects an altered capacity to respond to cognitive demands. This study compared how complexity induced by time constraints on processing affect cognitive function in individuals with ASD and typically-developing individuals. On a visual information-processing task, the "Subtle Cognitive Impairment Test," both groups exhibited sensitivity to time-constraints. Further, 65% of individuals with ASD demonstrated deficits in processing efficiency, possibly attributable to the effects of age and clinical comorbidities, like attention deficit hyperactivity disorder. These findings suggest that for some ASD individuals there are significant impairments in processing efficiency, which may have implications for education and interventions.