Supercomputers/Systems/Iridis 4
United Kingdom · operational · hpc
Iridis 4
Also known as Iridis4
Operated by University of Southampton at University of Southampton (Iridis) .
Researched with AI assistance, checked by scripts. These rows were researched by AI agents reading public operator, laboratory and vendor sources, appended by scripts and checked by automated validation; no subject-matter expert has reviewed them (how this site is made). A mechanical second-reader pass has since fetched every cited source: 1350 of 1581 systems have a readable citation that names them, and 64 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
- 227.03 TFlop/s
- Rpeak
- 249.60 TFlop/s
- Rmax ÷ Rpeak
- 91.0%
- Cores
- 12,000
- Power
- 249.26 kW
- Per watt
- 0.9 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.
How it compares
Ranked against the other machines in this dataset that report the same figure: those that first came into service within two years of Iridis 4, and those in United Kingdom. Computed from our tables; a metric is ranked only when at least eight peers report it.
| Metric | Value | Against its era | Against its country |
|---|---|---|---|
| Rmax | 227.03 TFlop/s | #171 of 227 · bottom 26% | #30 of 44 · bottom 34% |
| Energy efficiency | 0.9 GF/W | #114 of 186 · bottom 40% | #17 of 21 · bottom 21% |
| Rmax ÷ Rpeak | 91.0 % | #18 of 226 · top 8% | #5 of 44 · top 9% |
| Power draw | 249 kW | #141 of 188 · bottom 26% | #15 of 21 · bottom 31% |
Every metric is ranked largest-first, so a high power-draw rank means a big power draw, not a good one. Rmax ÷ Rpeak uses HPL-measured results only. Rankings move as machines are added; they describe this dataset, not the world.
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 iDataPlex DX360M4 (IBM Intelligent Cluster) | IBM | - | Reported | top500.orgsouthampton.ac.uk |
| Integrator | - Designed, integrated and supported by OCF | OCF | - | Reported | southampton.ac.uk |
| Accelerator | - Intel Xeon Phi coprocessors | Intel | - | Reported | southampton.ac.uk |
| CPU | Intel Xeon E5-2670 CPUs x86-64 · 8C · 2.6 GHz · 32 nm · 115 W Xeon E5-2670 8C 2.6GHz | Intel | - | Reported | top500.orgsouthampton.ac.uk |
| Interconnect | Mellanox InfiniBand FDR Interconnect Fat tree · 56 Gb/s per 4x port · About 1 microsecond Infiniband FDR | Mellanox NVDANASDAQ
rolls up to NVIDIA | - | Reported | top500.orgsouthampton.ac.uk |
The read
University of Southampton's fourth-generation Iridis cluster, switched on in October 2013 in a GBP 3.2 million deal: IBM Intelligent Cluster hardware integrated by OCF, with 12,200 Xeon E5-2670 cores, 1 PB of disc, 50 TB of memory and Intel Xeon Phi coprocessors, billed as four times Iridis 3 and with around 350 projects expected in its first year. TOP500 lists an IBM iDataPlex DX360M4 with FDR InfiniBand, 12,000 cores, Rmax 227.03 TF, Rpeak 249.6 TF and 249.26 kW, ranked 180 in Nov 2013 and 452 in Nov 2015; the 12,000 versus 12,200 core counts differ between the two sources. Its successor line is iridis-5.
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
Change history
- 2026-10-17 Iridis 4 added from its source pages
Nearby in scale
The machines closest to Iridis 4 by Rmax, smaller to larger.
- Cypress (Tulane) · USA, operational · 0.22 PFlop/s
- RWTH Compute Cluster 2011 · Germany, operational · 0.22 PFlop/s
- Gordon · USA, decommissioned · 0.22 PFlop/s
- Mustang (LANL) · USA, decommissioned · 0.23 PFlop/s
- Quinde I · Ecuador, decommissioned · 0.23 PFlop/s
- BURA · Croatia, operational · 0.23 PFlop/s
Related systems
Same site
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 |
|---|---|---|
| southampton.ac.uk | names system and part | Intel Xeon E5-2670, Mellanox InfiniBand FDR |
| top500.org | names system and part | Intel Xeon E5-2670, Mellanox InfiniBand FDR |
Checked 2026-10-18 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.