Recently, CPU speed increases only slowly, while the number of transistors per chip keeps growing exponentially. Consequently, processors with multi-core architectures are pervading the market. Unfortunately, most existing software still can not exploit the parallelism. Since modular software synthesis implementations typically simulate parallel hardware, they are designated to run on parallel hardware. We examine different approaches for parallelization of a modular software synthesizer and discuss their advantages and disadvantages with respect to both the performance gain and the impact on the software architecture.