Recent findings suggest that in dual-tasking the elements of the two tasks are associated across tasks and are stored in a conjoint memory episode, meaning that the tasks are not represented as isolated task-sets. In the current study, we manipulated between conditions the frequency distributions of short and long stimulus-onset asynchronies (SOAs). We tested whether a more serial processing mode induced by frequent long SOAs can reduce or even hinder participants to generate conjoint memory episodes. As an alternative, it is conceivable that conjoint memory episodes are an obligatory consequence of presenting two tasks within a single trial. For this purpose, we run two dual-task experiments and tested between consecutive trials whether the repetition of both stimulus-response mappings would lead to faster responses as compared to a partial repetition in which only one of the two tasks’ stimulus-response mapping repeated. The dual-tasks consisted of a visual-manual search task (VST) and an auditory-manual discrimination task (ADT). Overall the results suggest that the generation of a conjoint memory episode seems to be a default process after having processed the two tasks within a single trial, regardless of a more serial or parallel processing mode. The respective processing mode rather seemed to affect whether the participants tend to group or not to group the processing of the two tasks, thereby modulating the impact of the reactivated memory episode on task performance.