DiRAC BlueGene/Q

Also known as DiRAC Extreme Scaling Edinburgh BG/Q

Operated by EPCC at Advanced Computing Facility, Edinburgh .

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: 1.07 PFlop/s
Rpeak: 1.26 PFlop/s
Rmax ÷ Rpeak: 85.3%
Cores: 98,304
Power: 493.12 kW
Per watt: 2.2 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 Blue Gene/Q, six racks	IBM IBMNYSE	-	Verified	top500.org pos.sissa.it
CPU	IBM PowerPC A2 (Power BQC) CPUs PowerPC A2 · 18C · 1.6 GHz · 45 nm · 55 W Power BQC 16C 1.6GHz, 98,304 cores	IBM IBMNYSE	-	Reported	top500.org
Interconnect	IBM BlueGene/Q 5D torus Interconnect 5D torus · 2 GB/s per link per direction Custom Blue Gene/Q interconnect	IBM IBMNYSE	-	Reported	top500.org

The read

Six-rack IBM Blue Gene/Q run by EPCC for the STFC DiRAC facility, 20th on the June 2012 TOP500 and used for lattice QCD and other extreme-scaling work. TOP500 lists 98,304 Power BQC 16-core 1.6 GHz cores, 1.073 PFlop/s Rmax and 1.258 PFlop/s Rpeak, and a Peter Boyle paper in the PoS proceedings describes the Edinburgh BlueGene/Q DiRAC system as 1.26 PFlop/s in six racks. EPCC's article on Tesseract says the DiRAC BlueGene/Q service was retired in January 2018 and succeeded in March 2018 by the 844-node Extreme Scaling system Tesseract.

Timeline

2012 First operational source
2012-06 List debut at #20 (June 2012) source
2018-01 Decommissioned source

Public list appearances

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

#20: TOP500, June 2012 →

Site & facility

Advanced Computing Facility, Edinburgh

Location: Edinburgh, United Kingdom
Cooling: Direct liquid cooling
Commissioned: 1990

archer2.ac.uk

Change history

2026-10-02 Added DiRAC BlueGene/Q, Edinburgh

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
pos.sissa.it	does not name this system	-
top500.org	names system and part	IBM BlueGene/Q 5D torus

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