Supercomputers/Systems/ATERUI II
Japan · operational · hpc
ATERUI II
Also known as NS-05
Operated by National Astronomical Observatory of Japan .
Phase 1 seed dataset, compiled by hand. These rows were built from public operator, laboratory and vendor sources. A mechanical second-reader pass has since fetched every cited source: 1092 of 1153 systems have a readable citation that names them, and 40 are genuinely weakly sourced. Every claim carries its source and a confidence tier. Treat anything below verified as a lead, not a citation.
Measured performance
- Rmax
- 2.09 PFlop/s
- Rpeak
- 3.07 PFlop/s
- Rmax ÷ Rpeak
- 68.1%
- Cores
- 40,000
- Power
- 495.86 kW
- Per watt
- 4.2 GF/W
Figures are as last publicly reported for the configuration described below, not a live measurement. Where a system was upgraded in place, the post-upgrade configuration is shown and the earlier one appears in the timeline.
What this machine is made of
One row per supplier relationship. “Supplier at build” is the company that shipped the part at the time; where that company has since been acquired, the parent it rolls up to today is shown beside it. That distinction is what makes ticker-level aggregation possible across a thirty-year dataset.
| Role | Part | Supplier at build | Quantity | Confidence | Source |
|---|---|---|---|---|---|
| Integrator | - Cray XC50 (NS-05 ATERUI II) | Cray HPENYSE
rolls up to Hewlett Packard Enterprise | - | Reported | nao.ac.jptop500.org |
| CPU | Intel Xeon Gold 6148 CPUs x86-64 · 20C · 2.4 GHz · 14 nm · 150 W Intel Xeon Gold 6148 20C 2.4GHz (Skylake) | Intel | - | Reported | top500.org |
| Interconnect | Cray Aries Interconnect Dragonfly · About 10 GB/s per direction · Around 1 microsecond Cray Aries interconnect | Cray HPENYSE
rolls up to Hewlett Packard Enterprise | - | Reported | top500.org |
The read
Cray XC50 at the National Astronomical Observatory of Japan's Center for Computational Astrophysics, in operation from 1 June 2018 with 3.087 PFlop/s peak per NAOJ, billed as the world's fastest machine dedicated to astrophysical simulation. TOP500 lists 40,000 Xeon Gold 6148 cores on the Aries network and 2.09 PFlop/s Rmax, 117th on the June 2019 list. NAOJ's own announcement does not give the CPU type; that comes from the TOP500 entry.
Timeline
Public list appearances
Pointers only: rank and edition, linking to the canonical entry. We do not reproduce list tables. See sourcing policy.
Change history
- 2026-10-02 Added ATERUI II, NAOJ's astrophysics Cray XC50
Source check
We fetched this system's own citations and recorded whether each page actually mentions it. This is a corroboration signal, not a fact check, and it is published so you can see how well the sourcing holds up rather than take it on trust.
| Cited source | Result | Found on the page |
|---|---|---|
| top500.org | names system and part | Intel Xeon Gold 6148, Cray Aries |
| nao.ac.jp | names system only | - |
Checked 2026-10-09 by pnpm verify. Re-run it and the table changes with the web.
Further reading
Operating a supercomputer
Acceptance testing, why "installed" and "in production" are six months apart, and the machine lifecycle.
Inside a node
Latency-optimised versus throughput-optimised processors, NUMA, and the end of the host-to-device copy.
The interconnect
Topologies, why latency and tail behaviour matter more than bandwidth, and how the fabric market consolidated.