The DEEP projects have developed a variety of hardware and software technologies aiming at improving the efficiency and usability of next generation high-performance computers. They evolve around an innovative concept for heterogeneous systems: the Cluster-Booster architecture. In it, a general purpose cluster is tightly coupled to a many-core system (the Booster). This modular way of integrating heterogeneous components enables applications to freely choose the kind of computing resources on which it runs most efficiently. Codes might even be partitioned to map specific requirements of code-parts onto the best suited hardware. This paper presents for the first time measurements done by a real world scientific application demonstrating the performance gain achieved with this kind of code-partition approach.