Supercomputers/Systems/K computer
Japan · decommissioned · hpc
K computer
Also known as Kei
Operated by RIKEN at RIKEN Center for Computational Science.
Phase 1 seed dataset — under review. These rows were compiled by hand from public operator, laboratory and vendor sources, and have not yet been through a second-reader verification pass. Every claim carries its source and a confidence tier; treat anything below verified as a lead, not a citation.
Measured performance
- Rmax
- 10.51 PFlop/s
- Rpeak
- 11.28 PFlop/s
- Rmax ÷ Rpeak
- 93.2%
- Cores
- 705,024
- Power
- 12.66 MW
- Per watt
- 0.8 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 | Fujitsu | — | Reported | global.fujitsur-ccs.riken.jp |
| CPU | Fujitsu SPARC64 VIIIfx CPUs SPARC64 VIIIfx 2.0GHz | Fujitsu | 88,128 reported | Reported | global.fujitsur-ccs.riken.jp |
| Interconnect | Fujitsu Tofu Interconnect Interconnect Tofu interconnect | Fujitsu | — | Reported | global.fujitsur-ccs.riken.jp |
The read
The first system past ten petaflops, and Fujitsu's proof that a CPU-only design with a custom interconnect could still take the top position in the accelerator era. Its efficiency ratio — Rmax over Rpeak above 93% — has rarely been matched by heterogeneous systems since. Decommissioned in 2019 to clear the floor for Fugaku, which reused the site and the architectural argument.
Timeline
- 2006 Announced source
- 2011-06 List debut at #1 (June 2011) source
- 2011-06 First operational source
- 2019-08 Decommissioned source
Public list appearances
Pointers only — rank and edition, linking to the canonical entry. We do not reproduce list tables. See sourcing policy.
Site & facility
RIKEN Center for Computational Science
- Location
- Kobe, Japan
- Cooling
- Direct liquid cooling (warm water)
- Commissioned
- 2010