# Fugaku: every supplier in the machine

RIKEN Center for Computational Science · JP · system record on Compute Atlas: https://computeatlas.net/supercomputers/systems/fugaku

## Specs

- **accelerator:** none: CPU-only
- **host cpu:** Fujitsu A64FX (Armv8.2-A SVE 512-bit, 48 compute + 2 assistant cores, 2.0 GHz normal / 2.2 GHz boost, 32 GiB on-package HBM2)
- **integrator:** Fujitsu (units manufactured by Fujitsu IT Products Ltd.)
- **nodes:** 158,976 single-CPU nodes in 432 racks (396 racks of 384 nodes, 36 racks of 192 nodes)
- **memory:** 32 GiB HBM2 per node (1,024 GB/s), no DDR; 4.85 PiB total, 163 PB/s aggregate bandwidth
- **interconnect:** Tofu Interconnect D, 6D mesh/torus, controller on the CPU die (28 Gbps x 2 lanes x 10 ports per node), no external switch
- **storage:** Three layers: node-local and job-shared NVMe tier (about 1.6 TB SSD per 16 nodes), FEFS (Lustre-based) shared file system of about 150 PB on DDN SFA18K arrays, commercial cloud storage
- **cooling:** Water-cooled CPU memory units plus a custom water-cooling unit; RIKEN gives a 9:1 water-to-air cooling ratio for the system
- **power mw:** 29.9 MW (29,899.23 kW) on the full-system HPL run, listed from the 11/2020 TOP500 list through the 06/2026 list; an optimized run is listed at 26.25 MW (HPL 404.69 PFlop/s)
- **rmax pflops:** 442.01 PFlop/s (TOP500 June 2026 list)
- **rpeak pflops:** 537.21 PFlop/s (TOP500 June 2026 list)
- **status note:** First unit shipped December 2019; TOP500 installation year 2020; a 396-rack partial system (415.53 PFlop/s) was first listed in June 2020 and the full 442.01 PFlop/s result from November 2020

Unmarked companies come from the operator's or the vendor's own pages (r-ccs.riken.jp, fujitsu.com, top500.org, and the supplier's own page for DDN, Staubli and Molex); reported companies come from named trade press or independent analyst reporting whose article body was read in full, not just the headline. This is a map of who plays where, not a confirmed bill of materials: RIKEN R-CCS, Fujitsu, TOP500 and named supplier pages (DDN, Staubli, Molex), plus one independent technical report (Dongarra, 2020), researched 2026-10-02

## Lines

1. System architecture, rack design and integration (jointly developed by RIKEN and Fujitsu; 432 racks, 384 nodes per full rack)
   - parts: Rack-scale systems (4.01); EMS, system integration & rack-level test (4.02)
   - companies: Fujitsu (designer and integrator; units manufactured by its subsidiary Fujitsu IT Products Ltd.)
   - sources: https://info.archives.global.fujitsu/global/about/resources/news/press-releases/2019/1202-01.html https://www.r-ccs.riken.jp/en/fugaku/about/
2. Compute node and board (1 CPU per node; 2 nodes per CPU Memory Unit; 16 nodes per Bunch of Blades; 48 per shelf; 384 per rack)
   - parts: GPU baseboards & compute trays (4.03)
   - companies: Fujitsu (designed the CPU Memory Unit board and node packaging)
   - not confirmed: rack power supplies and fans (included in the measured power per Dongarra, but no maker named in any source read)
   - sources: https://www.r-ccs.riken.jp/en/fugaku/about/
3. Cabled backplane and board-level connectors (backbone between the system's circuit boards; connectors on each CPU)
   - parts: Board-level connectors & sockets (4.07)
   - companies: Molex (supplied cabled backplane and 30 standard plus 8 specialty components)
   - sources: https://www.molex.com/en-us/blog/molex-innovation-powers-the-fugaku-supercomputer
4. A64FX CPU design (Fujitsu in-house core and memory system; 4 core-memory groups, 512-bit SVE, Tofu-D controller on die)
   - parts: Server CPUs (1.05)
   - companies: Fujitsu (designer of the A64FX)
   - sources: https://www.fujitsu.com/global/about/resources/publications/technicalreview/2020-03/article03.html https://www.r-ccs.riken.jp/en/fugaku/about/
5. Arm instruction set (Armv8.2-A with the SVE vector extension, co-specified by Fujitsu)
   - parts: Server CPUs (1.05)
   - companies: Arm (instruction-set architecture and SVE extension; Fujitsu was lead partner on the SVE specification)
   - sources: https://www.fujitsu.com/global/about/resources/publications/technicalreview/2020-03/article03.html https://newsroom.arm.com/blog/fujitsu-a64fx-arm
6. A64FX die fabrication and 2.5D packaging with four on-package HBM2 stacks (32 GiB, 1,024 GB/s per node)
   - parts: Leading-edge foundry (1.09); 2.5D/3D advanced packaging (1.11); HBM (2.01)
   - companies: TSMC (7 nm FinFET fabrication and CoWoS interposer packaging)
   - not confirmed: HBM2 stack maker (Samsung, SK hynix and Micron are the only HBM producers, but no RIKEN, Fujitsu or supplier page found names which one supplied the A64FX stacks); OSAT or assembly house for the finished package (if any besides the foundry)
   - sources: https://www.fujitsu.com/global/about/resources/publications/technicalreview/2020-03/article03.html https://www.hpcuserforum.com/wp-content/uploads/2021/09/Supercomputer-Fugaku_Riken-R-CCS_M.-Sato_Sept-2021-HPC-UF.pdf
7. On-die SerDes, HBM I/O and SRAM IP in the A64FX
   - parts: ASIC design services, IP & EDA (1.03)
   - companies: Broadcom* (SerDes, HBM I/O and SRAM blocks per a single independent report)
   - sources: https://www.netlib.org/utk/people/JackDongarra/PAPERS/icl-utk-1379-2020.pdf
8. Tofu Interconnect D (on-die network controller and router, 6D mesh/torus, 6 network interfaces at 6.8 GB/s each, about 216,864 cables)
   - parts: NICs / SuperNICs (1.06); Scale-out switch ASICs (3.02); Copper: DAC / ACC / AEC cables (3.09); Fiber, connectors, structured cabling (3.11)
   - companies: Fujitsu (designed the Tofu-D controller and router; no separate NIC or switch)
   - not confirmed: makers of the 97,632 optical (855,101 m) and 119,232 electrical (38,552 m) Tofu cables, and of the optical modules in the cables
   - sources: https://www.r-ccs.riken.jp/en/fugaku/about/
9. Second-tier shared storage (FEFS on Lustre; DDN SFA18K arrays, 5x SFA18KE + 25x SFA18KXE)
   - parts: AI storage systems (2.10)
   - companies: DDN (SFA18K Series arrays hosting the object storage servers; tested with 5 SFA18KE and 25 SFA18KXE); Fujitsu (FEFS file system (Lustre-based) and the first-tier LLIO layer)
   - not confirmed: hard drive makers inside the DDN expansion enclosures (DDN says hard drives are used as OSTs but does not name a maker); NVMe SSD maker for the first-tier node-local storage (about 1.6 TB per 16 nodes)
   - sources: https://www.ddn.com/press-releases/ddn-sfa18k-supercomputer-fugaku/ https://www.r-ccs.riken.jp/en/fugaku/about/
10. Liquid-cooled blades (water-cooled CPU memory units; quick-release couplings between each blade and the rack chassis, 384 sets per rack)
   - parts: Quick disconnects (5.03); Direct-to-chip cold plates (5.01)
   - companies: Stäubli (CGD quick-release couplings for hot-swappable blades); Fujitsu (designed the water-cooled CPU memory unit and rack)
   - not confirmed: cold plate maker; coolant distribution unit and facility chiller and pump vendors (RIKEN says the Kobe plant was expanded but names no vendors)
   - sources: https://www.staubli.com/us/en/fluid-connectors/success-story/Fujitsu-IT-cooling.html

* reported: named trade press or analyst reporting rather than the operator or vendor.

## What could not be confirmed

The HBM2 stack maker, the optical and electrical Tofu cable makers, the SSD and hard-drive makers behind the two storage tiers, and the rack power supplies and facility chillers and pumps are not named in any RIKEN, Fujitsu or supplier page found, so none are listed. RIKEN confirms a 9 to 1 water-to-air cooling ratio and an expanded chiller and pump plant at the Kobe site but names no equipment vendor.