ITO Subsystem A

Also known as ITO; Kyushu University ITO

Operated by RIIT, Kyushu University at Kyushu University Ito Campus .

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: 4.54 PFlop/s
Rpeak: 6.91 PFlop/s
Rmax ÷ Rpeak: 65.7%
Cores: 72,000
Power: -
Per watt: - 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	- Fujitsu PRIMERGY CX2550/CX2560 M4	Fujitsu 6702TSE	-	Reported	top500.org info.archives.global.fujitsu
CPU	- Two Intel Xeon Gold 6154 18C 3GHz per node, 2,000 nodes	Intel INTCNASDAQ	2,000 reported	Reported	top500.org
Interconnect	Mellanox InfiniBand EDR Interconnect Fat tree · 100 Gb/s per 4x port · About 0.9 microseconds Mellanox InfiniBand EDR 100 Gbps	NVIDIA NVDANASDAQ	-	Reported	top500.org info.archives.global.fujitsu

The read

The large-scale CPU subsystem of Kyushu University's ITO supercomputer: a Fujitsu PRIMERGY CX2550/CX2560 M4 cluster of 2,000 nodes with two Xeon Gold 6154 (18-core, 3.0 GHz) CPUs on Mellanox InfiniBand EDR. TOP500 lists 72,000 cores, Rmax 4.54 and Rpeak 6.91 PFlop/s, listed from June 2018 to November 2023 (rank 164 at the end). Fujitsu announced the order in June 2017 for the whole ITO system (about 10 PFlop/s with a GPU subsystem), and a Fukuoka news item reports full-scale operation from February 2018.

Timeline

2017-06 Announced source
2018 First operational source
2019-11 List debut at #45 (November 2019) source
2024-02-29 Decommissioned source

Public list appearances

Pointers only: rank and edition, linking to the canonical entry. We do not reproduce list tables. See sourcing policy.

#45: TOP500, November 2019 →

Site & facility

Kyushu University Ito Campus

Location: Fukuoka, Japan

cc.kyushu-u.ac.jp top500.org

Change history

2026-10-02 Added ITO Subsystem A, Kyushu University's Skylake cluster, 45th on the November 2019 TOP500
2026-10-02 Marked ITO Subsystem A decommissioned

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
info.archives.global.fujitsu	names system and part	Mellanox InfiniBand EDR
top500.org	names system and part	Mellanox InfiniBand EDR

Checked 2026-10-09 by pnpm verify. Re-run it and the table changes with the web.