Most Raspberry Pis used in parallel

The most Raspberry Pis used in parallel is 750, built by BitScope (Australia) and IT services provided by SICORP (USA) at the Los Alamos National Laboratory in New Mexico, USA, delivered on 13 November 2017.

The Scope Blade cluster is a system that joins 750 of the ubiquitous single-board computers to give it a total of 3,000 working cores.

The point of the Los Alamos cluster isn't to set speed records or do important calculations, but rather to provide an accessible testing environment for students and software developers. The BitScope Blade has the same kind of architecture (lots of physically separate processors running in parallel) as a real supercomputer, which means it can replicate the quirks of real supercomputers in the way that virtual machines can't – things like the timing issues that occur when two parts of the same calculation are being handled by two physically distant processors.

Importantly it can be operated for a fraction of the cost of a real supercomputer, and without interrupting programs on the main system. This allows users to test new ideas and get practice in the notoriously challenging field of supercomputer programming, without using millions of dollars in supercomputer time and several megawatts of electricity. The LANL plans to expand the system to 10,000 cores in the near future.