Supercomputers/Systems/Lassen
USA · decommissioned · hpc
Lassen
Operated by Lawrence Livermore National Laboratory at Livermore Computing Center .
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
- 18.20 PFlop/s
- Rpeak
- 23.05 PFlop/s
- Rmax ÷ Rpeak
- 79.0%
- Cores
- 288,288
- 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 | - IBM Power System AC922 | IBM | - | Reported | top500.org |
| Accelerator | NVIDIA Tesla V100 Accelerators CUDA (Volta GV100) · 5,120C · 1.53 GHz · 12 nm · 300 W 3,168 NVIDIA Tesla V100 GPUs | NVIDIA | 3,168 reported | Reported | hpc.llnl.govtop500.org |
| CPU | IBM POWER9 22C CPUs POWER · 22C · 3.07 GHz · 14 nm · 190 W IBM POWER9 22C 3.1GHz | IBM | - | Reported | top500.org |
| Interconnect | Mellanox InfiniBand EDR Interconnect Fat tree · 100 Gb/s per 4x port · About 0.9 microseconds Dual-rail Mellanox EDR InfiniBand | NVIDIA | - | Reported | top500.org |
| Operating system | Red Hat Enterprise Linux Operating systems Linux distribution · Open source, commercial support subscription Red Hat Enterprise Linux | Red Hat | - | Reported | top500.org |
The read
LLNL's unclassified IBM POWER9 and NVIDIA V100 system, tenth on the June 2019 TOP500. LLNL's own page now titles it decommissioned but gives no date, so none is recorded. LLNL counts 34,848 CPU cores and 3,168 GPUs; TOP500's 288,288 also counts GPU cores, so the two are not comparable and the TOP500 figure is used for cores. The TOP500 entry is the only source for the figures and no independent source confirms them, so the tier is reported. Only the parts a fetched source names are recorded as edges.
Timeline
Public list appearances
Pointers only: rank and edition, linking to the canonical entry. We do not reproduce list tables. See sourcing policy.
Site & facility
Livermore Computing Center
- Location
- Livermore, CA, USA
- Cooling
- Direct liquid cooling (warm water)
- Commissioned
- 1996
Change history
- 2026-09-20 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 |
|---|---|---|
| hpc.llnl.gov | names system, part and count | IBM POWER9 22C, Mellanox InfiniBand EDR · counts: 3168 |
| top500.org | names system and part | IBM POWER9 22C, NVIDIA Tesla V100, Mellanox InfiniBand EDR |
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.