El Capitan (supercomputer)

Hewlett Packard Enterprise El Capitan, is an upcoming exascale supercomputer, hosted at the Lawrence Livermore National Laboratory in Livermore, United States and projected to become operational in 2024. It is based on the Cray EX Shasta architecture. When deployed, El Capitan is projected to displace Frontier as the world's fastest supercomputer.

Design
El Capitan will use an unknown number of AMD Instinct MI300A accelerated processing units (APUs). The MI300A consists of 24 Zen4 based CPU cores, and a CDNA3 based GPU integrated onto a single organic package, along with 128GB of HBM3 memory.

The floor space and number of racks for El Capitan have not yet been announced.

Blades are interconnected by an HPE Slingshot 64-port switch that provides 12.8 terabits/second of bandwidth. Groups of blades are linked in a dragonfly topology with at most three hops between any two nodes. Cabling is either optical or copper, customized to minimize cable length. Total cabling runs 145 km.

El Capitan uses an APU architecture, where the CPU and GPU share an internal on-chip coherent interconnect.

History
El Capitan was ordered as a part of the Department of Energy's CORAL-2 initiative, intended to replace Sierra (supercomputer), an IBM/NVIDIA machine deployed in 2018. LLNL partnered with HPE Cray and AMD to build the system.

Three El Capitan prototypes – named rzVernal, Tioga, and Tenaya – themselves were powerful enough to be listed on the TOP500 supercomputer list in June, 2023. rzVernal reached 4.1 petaflops. In early July, the first components of El Capitan were installed at Lawrence Livermore, with complete installation expected by mid 2024.