Event-driven architecture has been widely adopted in the software industry in recent years. This adoption is motivated by the increase in software modularity, and mainly the desired performance of decomposed monolithic applications. Although it has become popular, the current literature lacks studies that demonstrate the impact of event-driven architecture on performance. Hence, developers and architects end up adopting event-driven architecture without empirical evidence, but considering “expert advice.” This study, therefore, reports an empirical study on the impact of the adoption of event-driven architecture on performance. For this, the performance of an application implemented with an event-based architecture was compared with the performance of the same application implemented using monolithic architecture. The comparison was made using metrics such as CPU usage, memory, response time, throughput, and total packages sent and received. The results, supported by statistical tests, show that the monolithic architecture, compared to the event-driven architecture, consumes less computational resources and has better response times. Finally, this study reflects on the adoption of event-driven architecture, as well as points out challenges and implications that need to be considered by the scientific community in future research.