This study investigates the effects of e-groups on well-being and performance, using a collective approach and an objective performance indicator Furthermore, it includes collective efficacy as a moderator and negative (anxiety) as well as positive (engagement) well-being. A lab experiment with an interval of 3 weeks was performed among 140 students who were randomly distributed across 18 groups using a chat-internet program and 10 groups working face to face. Half the groups performed under time pressure. Results confirm the moderating role of perceived collective efficacy on well-being and task performance. All groups working under time pressure and low in collective efficacy show an increase in collective anxiety Chat-internet groups under time pressure show an increase in collective engagement but only when they feel high in collective efficacy. Finally, task performance was poorer in chat groups, working under time pressure, and with low levels of collective efficacy than in the other groups.