During the last years chat based instant messaging has become a part of the normal communication culture. Instant messaging based chat is now rapidly becoming a mainstream communication medium even in business environments. The same is becoming true for Voice over IP enabled audio communication. Skype, a high quality VoIP software has been downloaded over 200 million times and internet providers start to sell transparent VoIP products, which are usable with ordinary telephones. But these new technologies require new communication choices. We conducted an experiment to observe the effect of these new communication media on groups of four using chat or audio communication to work on tasks of uncertainty or equivocality. The results showed that audio groups were significantly more productive than chat groups for tasks of equivocality, while chat communication groups proved to be at least as productive as audio groups on tasks of uncertainty. Therefore we wanted to explore further, why these effects happened and what factors influenced the productivity of the groups. Based on our previous research and the media richness theory and the theory of media synchronicity the paper poses the hypothesis, that audio communication is faster, while chat communication is more efficient.