Germany · decommissioned · hpc

Hazel Hen

Operated by HLRS at HLRS, University of Stuttgart .

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: 5.64 PFlop/s
Rpeak: 7.40 PFlop/s
Rmax ÷ Rpeak: 76.2%
Cores: 185,088
Power: 3.62 MW
Per watt: 1.6 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	- Cray XC40	Cray HPENYSE rolls up to Hewlett Packard Enterprise	-	Reported	top500.org kb.hlrs.de
Interconnect	Cray Aries Interconnect Dragonfly · About 10 GB/s per direction · Around 1 microsecond Cray Aries interconnect	Cray HPENYSE rolls up to Hewlett Packard Enterprise	-	Reported	top500.org kb.hlrs.de
Operating system	Cray Linux Environment Operating systems Linux, Cray-customised · Proprietary layer over open-source Linux Cray Linux Environment	Cray HPENYSE rolls up to Hewlett Packard Enterprise	-	Reported	top500.org

The read

HLRS's Cray XC40 with 185,088 Haswell cores, eighth on the November 2015 TOP500, shut down on 25 February 2020 and replaced by Hawk, according to HLRS's own wiki, the only source for both facts. TOP500 is the only source for Rmax, Rpeak and core count, so the tier is reported.

Timeline

2015 First operational source
2015-11 List debut at #8 (November 2015) source
2020-02 Shut down February 25 and replaced by successor system Hawk source
2020-02 Decommissioned source

Public list appearances

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

#8: TOP500, November 2015 →

Site & facility

HLRS, University of Stuttgart

Location: Stuttgart, Germany
Cooling: Direct liquid cooling
Commissioned: 1996

hlrs.de

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
kb.hlrs.de	names system and part	Cray Aries, Cray Linux Environment
top500.org	names system and part	Cray Aries, Cray Linux Environment

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