I agree with Michel. Architectures are aplenty for research and practice. One has to be careful of choosing architectures with benchmarking approaches and studying the fit between requirements and best practices. Shall be nice if the context is elaborated little more.
I agree with Michel and Harekrishna. However, your question is a little bit tricky. Nowadays, supercomputers are machines that use massively the distributed computing. In terms of absolute performance, the Tianhe-2 (MilkyWay-2) is the most powerful architecture with a Linpack Performance (Rmax) of 33,862.7 TFlop/s (source: www.top500.org). This architecture consists of 3,120,000 cores (each one is a Intel Xeon E5-2692v2 12C 2.2GHz). In any case, it is important to know the context of your problems in order to give a better answer.