The University of Bristol is leading a £3m project to build the world’s largest ARM-based super computer.

Almost all of today’s supercomputers use x86 processors, but instead, the new supercomputer, called Isambard, will have 10,000 64bit ARM cores and it will be the largest production system in the world. It is being developed by researchers at Bristol, Bath, Cardiff and Exeter along with the Met Office and super computer maker Cray, which has its European headquarters and research centre in Bristol.

The Isambard supercomputer will sit between the large national Archer HPC service and the local high performance computing (HPC) clusters within individual universities. The project is one of seven announced by the EPSRC this week, and these projects, from Bristol to Edinburgh, Oxford and Cambridge, will have national access so users across the UK can get access to a wide range of technologies. Bristol researchers are also involved with the project in Edinburgh to develop new supercomputer storage systems.

Vulcan logic

Isambard will be one of the world’s first systems to be based on the Vulcan server-class chip being developed by Broadcom, which also has a software development centre in Bristol. Details of this device are still under wraps, but it promises much more memory bandwidth rather than higher peak performance, making it very attractive for researchers around the country tackling big problems. Hundreds of cards such as the Cray blades (pictured above) will be combined in the supercomputer.

“Isambard could be the first of a new generation of ARM-based supercomputers”


“Isambard is an exciting experiment,” said project leader Simon McIntosh-Smith, Professor of High Performance Computing at the University of Bristol. “If we discover that ARM processors are competitive in HPC, then Isambard could be the first of a new generation of ARM-based supercomputers, ushering in an era of wider architectural choice, with greater opportunities for differentiation between supercomputer vendors. These outcomes should mean that scientists can choose systems more highly optimised to solve their problem, delivering even more exciting scientific breakthroughs at greater cost effectiveness than ever before.”

The team is also providing a service to enable algorithm development and the porting and optimisation of scientific codes to ARM64 machines. This algorithm and software effort is a crucial part of any evaluation of different processor architectures, and there are multiple ARM-based HPC projects underway around the world that could use the new supercomputer.

Isambard will also include a small number of processors based on other advanced architectures, such as Intel’s latest Xeon Phi (based on their Knights Landing many-core CPU), and NVIDIA’s latest Pascal based P100 Tesla chips that use hundreds of smaller graphics processing units (GPUs) to power the computer.

You can see more on the project on the ESPRC Isambard: The Future of High Performance Computing page