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ARCHER2 hardware

System overview

ARCHER2 is a HPE Cray EX supercomputing system which has a total of 5,860 compute nodes. Each compute node has 128 cores (dual AMD EPYC 7742 64-core 2.25GHz processors) giving a total of 750,080 cores. Compute nodes are connected together by a HPE Slingshot interconnect.

There are additional User Access Nodes (UAN, also called login nodes), which provide access to the system, and data-analysis nodes, which are well-suited for preparation of job inputs and analysis of job outputs.

Compute nodes are only accessible via the Slurm job scheduling system.

There are two storage types: home and work. Home is available on login nodes and data-analysis nodes. Work is available on login, data-analysis nodes and compute nodes (see I/O and file systems).

This is shown in the ARCHER2 architecture diagram: ACRHER2 architecture

Compute node details

The compute nodes each have 128 cores. They are dual socket nodes with two 64 core AMD EPYC 7742 processors.


Note due to Simultaneous Multi-Threading (SMT) each core has 2 threads, therefore a node has 128 cores / 256 threads. Most users will not want to use SMT, see Launching parallel jobs.

Component Details
Processor 2x AMD Zen2 (Romes) EPYC 7742, 64-core, 2.25 Ghz
Cores per node 128
NUMA structure 8 NUMA regions per node (16 cores per NUMA region)
Memory per node 256 GB (standard), 512 GB (high memory)
Memory per core 2 GB (standard), 4 GB (high memory)
L1 cache 32 kB/core
L2 cache 512 kB/core
L3 cache 16 MB/4-cores
Vector support AVX2
Network connection 2x 100 Gb/s injection ports per node

ARCHER2 node diagram

Memory details

The 5,276 standard nodes each have 256 GB and the 584 high memory nodes each have 512 GB. All memory is 8-channel, DDR4 3200MHz with 204.8 GB/s peak bandwidth.

Interconnect details

ARCHER2 has a HPE Slingshot interconnect with 200 Gb/s signalling. It uses a dragonfly topology:

  • Nodes are organized into groups.

    • 128 Nodes in a group.
    • Electrical links between Network Interface Card (NIC) and switch.
    • 16 switches per group.
    • 2x NIC per node.
    • All-to-all connection amongst switches in a group using electrical links.
  • All-to-all connection between groups using optical links.

    • 2 groups per ARCHER2 Cabinet.