Japan · decommissioned · hpc

Oakleaf-FX

Operated by University of Tokyo at University of Tokyo, Kashiwa 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: 1.04 PFlop/s
Rpeak: 1.14 PFlop/s
Rmax ÷ Rpeak: 91.9%
Cores: 76,800
Power: 1.40 MW
Per watt: 0.7 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 PRIMEHPC FX10	Fujitsu 6702TSE	-	Verified	info.archives.global.fujitsu theregister.com
CPU	Fujitsu SPARC64 IXfx CPUs SPARC64 · 16C · 1.848 GHz one 16-core SPARC64 IXfx per node, 4,800 nodes	Fujitsu 6702TSE	4,800 reported	Verified	info.archives.global.fujitsu theregister.com
Interconnect	Fujitsu Tofu Interconnect Interconnect 6D mesh/torus · 5 GB/s per link per direction Tofu 6D mesh/torus interconnect	Fujitsu 6702TSE	-	Verified	info.archives.global.fujitsu theregister.com

The read

The first installation of Fujitsu's PRIMEHPC FX10, at the University of Tokyo's Information Technology Center on the Kashiwa Campus, the same site later used for Wisteria/BDEC-01, already in this dataset. 4,800 SPARC64 IXfx nodes (76,800 cores total, 150 TB of memory) on Fujitsu's Tofu 6D mesh/torus interconnect, ordered in November 2011 and operational from 2 April 2012, 18th on the June 2012 TOP500 list. Fujitsu's own press release and The Register's independent report agree on the node count, the processor, the interconnect and the 1.4 MW power figure; TOP500's measured Rmax LINPACK result is not corroborated elsewhere, so the tier stays reported. No decommissioning notice was found for this specific installation, so status is carried as last documented rather than inferred.

Timeline

2012-04 First operational source
2012-06 List debut at #18 (June 2012) source
2018-03-30 Decommissioned source

Public list appearances

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

#18: TOP500, June 2012 →

Site & facility

University of Tokyo, Kashiwa Campus

Location: Kashiwa, Chiba, Japan
Commissioned: 2021

cc.u-tokyo.ac.jp kashiwa.u-tokyo.ac.jp

Change history

2026-10-02 Marked Oakleaf-FX decommissioned
2026-09-23 Added, with a rank pointer on the edition where it ranked highest

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
theregister.com	names system, part and count	Fujitsu SPARC64 IXfx, Fujitsu Tofu Interconnect · counts: 4800
top500.org	names system and part	Fujitsu SPARC64 IXfx, Fujitsu Tofu Interconnect

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