rCUDA is designed to provide the best performance. In the plot you can see a comparison among the performance of P2P memory copies (data copies among GPUs) carried out with CUDA using the PCIe link within a single node and the performance attained by rCUDA when both GPUs are located in different remote servers and connected by InfiniBand. Three different GPU generations are considered. As you can see, using rCUDA does not mean a performance degradation.