Distributing applications at first decreases performance of the overall systems. Computer networks are slower than communication within a single host. Therefore networking will always come with a certain performance overhead.

The overhead in performance is not only caused by the communication itself, but also the need to synchronize. Synchronization within a single process already consumes certain processing time, and this impact is much bigger when distribution is involved.

However, despite this overhead in performance, distribution eventually increases the overall performance of the system as its applications scale out. Scaling horizontally always comes with a certain performance overhead compared to a single instance.