Fujitsu A64FX


The A64FX is an ARM architecture microprocessor designed by Fujitsu. The processor is replacing the SPARC64 V as Fujitsu's processor for supercomputer applications. It is powering the Fugaku supercomputer.

Design

Fujitsu collaborated with ARM to develop the processor; it will be the first processor to use the ARMv8.2-A Scalable Vector Extension SIMD instruction set with 512-bit vector implementation. A prototype computer using the processors was ranked as the 159th fastest computer in the world on the Top 500 list in November 2019.
The processor uses 32 gigabytes of HBM2 memory with a bandwidth of 1 TB per second. The processor contains 16 PCI Express generation 3 lanes to connect to accelerators, e.g. GPGPUs and FPGAs. The reported transistor count is about 8.7 billion.
Each CPU has 48 cores built as a "node" - the Fugaku node has 4 "assistant cores", however Fujitsu intends to produce lower specification machines with zero or two assistant cores.

Implementations

Fujitsu designed the A64FX for the Fugaku. As of June 2020 the Fugaku is the fastest supercomputer in the world by TOP500 rankings. Fujitsu intends to sell smaller machines with A64FX processors. Anandtech reported in June 2020 that the cost of a PRIMEHPC FX700 server, with 2 A64FX nodes, was .
Cray is developing supercomputers using the A64FX. The Isambard 2 supercomputer is being built for a consortium in the United Kingdom, led by the University of Bristol and also including the Met Office, using the Fujitsu processors. It is an upgrade to the Isambard supercomputer which was built with the Cavium ThunderX2, another ARM architecture microprocessor.