Modularity is a key architectural concept in building highly efficient HPC systems which match the computational and data processing needs of modern HPC applications and workflows. Accelerated Clusters replicate one node architecture (usually CPUs plus a number of accelerators, such as GPUs) and thus provide a fix ratio of CPU and accelerator resources; applications which require different ratios, or accelerators not present in the “master” node, will run with reduced performance, or leave significant parts of the nodes it runs on unused.