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Topic dossier · Data and Compute

High performance computing

High-performance computing runs the weather forecasts, climate projections, engineering simulations, genomics and AI training that modern science and public services rely on. National capacity depends on machines, software, skilled people, energy and long-term funding. This page sets out how HPC capacity is built and used, how it is measured, and what evidence serves the research funders and agencies that plan national computing.

01In brief

The short answer.

High-performance computing is the use of supercomputers and parallel processing to run large simulations and analyses, from weather forecasts to genomics and AI. National capacity depends on machines that age fast, software and skilled people to use them, power supply and long-term funding.

02Geography

Connected activity in the contiguous United States.

For high performance computing, in GCRI's spatial-intelligence reading, the map opens on night lights, population density and true-colour imagery with true colour from NASA GIBS, framed on the contiguous United States; every other NASA layer, live feed and forecast waits in the layer list.

The interactive map needs JavaScript; the layer list and sources are below.

Layers 3

Connected activity, for this page

Latest available

NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth

Loading the latest NASA imagery.

Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.

For high performance computing, in GCRI's spatial-intelligence reading, the map opens on night lights, population density and true-colour imagery with true colour from NASA GIBS, framed on the contiguous United States; every other NASA layer, live feed and forecast waits in the layer list.Satellite and model products as NASA publishes them, each with its own date; indicators, not assessments of any place; claim ceiling INTEGRATED.

Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · Copernicus Sentinel-2 L2A · NASA HLS S30Sources and licences

  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • VIIRS Black Marble night-time lights, NASA Goddard Space Flight Center; distributed by the NASA Level-1 and Atmosphere Archive and Distribution System (LAADS DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). CC BY 4.0
  • VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • GPM IMERG precipitation, NASA Precipitation Processing System; distributed by the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
  • © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). ODbL
  • Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into H3 cells where shown (modified). NASA open data
  • Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
  • Globe: MapLibre GL JS 6.9.1, BSD-3-Clause, © MapLibre contributors.
  • Observed (EO): Copernicus Sentinel-2 L2A (contains modified Copernicus Sentinel data 2026), Microsoft Planetary Computer
  • Observed (EO): NASA HLS S30 (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA's Global Imagery Browse Services (GIBS), part of NASA's Earth Science Data and Information System (ESDIS).
  • Optional layers (35 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.

Layers and dates

  • Night-time lights, daily: VIIRS Black Marble (VNP46A2), NASA LAADS DAAC · 12 Oct 2026
  • Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
  • True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
  • Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
  • Flood water, 3-day composite: VIIRS Global Flood Product, NASA LANCE · 14 Oct 2026
  • Precipitation rate, daily mean: GPM IMERG, NASA GES DISC · 12 Oct 2026

03The question

High performance computing: how the risk develops.

HPC/GPU workloads and scientific compute. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.

Mechanism

Capability and capacity differ

Some problems need one very large machine running one job; others need many smaller jobs. Planning for one does not serve the other.

Mechanism

Machines age fast

Supercomputers are replaced every few years as performance per watt improves. Gaps between systems interrupt the work of forecasting and research centres.

Mechanism

Software and skills limit use

Codes must be ported and optimised for new architectures such as GPUs. Shortages of research software engineers leave capacity underused.

Mechanism

Power sets the ceiling

Large systems draw megawatts. Energy cost and grid capacity increasingly decide where and how large new machines can be.

04Key terms

Terms used on this page.

Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.

TermDefinition
Capability computingUsing a large share of a supercomputer for a single, very large job.
Capacity computingRunning many smaller jobs at the same time to maximise total throughput of a system.
Research software engineerA professional who develops and maintains software used in research.
05Indicators

What is measured, and how well.

Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.

IndicatorUnitCadenceSource typeLabel
Sustained performance on standard benchmarksfloating point operations per secondtwice yearlyTOP500 listOBSERVED
Energy efficiencyfloating point operations per watttwice yearlyGreen500 listOBSERVED
System utilisationpercent of available node hours usedmonthlyCentre usage recordsOBSERVED
Allocation oversubscriptionratio of requested to available hoursper callAllocation recordsOFFICIAL
Research software engineers employedcountannualCentre staffing recordsREPORTED
Codes ported to acceleratorspercent of major community codesper assessmentCentre reportsREPORTED
06Canvas

From sources to decisions.

The topic as a computational graph: named sources feed the methods, an evidence review gates the outputs, and the decisions stay with the authorities that hold them.

Pipeline canvas · High performance computing as a run graphDesign, not a record
High performance computing: build, test and release in Nexus FoundryA request opens a workspace; data are ingested and validated; the model is built and tested on held-out data; an independent gate approves release with limits; the workspace is stood down and the record kept. Design of the process, not a record of a run.

Fig. 02Nodes carry their type, two metric rows and a state; connectors show what feeds what; dashed frames name the owners; the timeline is the cadence. Design of the pipeline, not a record of a run.

07Sources

Where the evidence comes from.

Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.

SourceWhat it givesLicence class
TOP500 and Green500 listsPerformance and energy efficiency of the most powerful systemsPublic, TOP500 terms
EuroHPC Joint Undertaking reports and access callsEuropean supercomputers and allocationPublic, EU terms
National HPC centre annual reportsUsage, allocation and science outputsPublic records, terms per centre
ESFRI roadmap and landscape analysisEuropean research infrastructure planningPublic, EU terms
WMO reports on numerical weather prediction capacityComputing used by meteorological servicesPublic, WMO terms
08Decisions

Who decides, and what the evidence serves.

Data and Compute prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.

Who decidesThe questionEvidence this page serves
Research funders and science ministriesWhat computing capacity to fund and whereCapacity and demand reviews; oversubscription
HPC centresHow to allocate time and support usersUtilisation and allocation analyses
Meteorological and climate servicesWhen to procure the next systemPerformance and workload evidence

Outputs this topic produces

  • National HPC capacity and demand reviews
  • Allocation and utilisation analyses
  • Workforce and software readiness assessments
  • Evidence notes for computing investment plans
09Core questions

What HPC experts ask.

  • Which workloads need tightly coupled supercomputers, and which can run on cloud or distributed resources?
  • How should capacity be balanced between traditional simulation and AI workloads, which favour different architectures?
  • Can scientific codes be ported to new architectures without years of rewriting?
  • Who gets access, and how are competing scientific priorities weighed?
10Mechanisms

What makes HPC distinct.

Large simulations divide a problem into many pieces that must exchange data constantly. Performance depends not only on processor speed but on memory bandwidth, the interconnect between nodes and input and output to storage. A system that is fast on paper can be slow for a given code if these are unbalanced.

Accelerators such as GPUs deliver much more arithmetic per unit of energy for suitable workloads, which is why AI training uses them. But many scientific codes were written for conventional processors and need substantial effort to use accelerators well. Architecture shifts therefore create a software burden and a skills burden, not just a procurement decision.

11Methods and limits

How capacity is planned and evaluated.

  1. 01

    Workload analysis

    Profiling the actual codes and data volumes a community runs. Limits: future workloads, especially AI, are hard to predict.

  2. 02

    Benchmarks

    Standard tests of computing performance. Limits: no benchmark represents all workloads, and peak figures overstate real performance.

  3. 03

    Capacity planning

    Modelling demand, utilization and replacement cycles with optimization and operations research. Limits: depends on funding cycles and hardware availability.

  4. 04

    Energy efficiency analysis

    Measuring useful work per unit of energy, linked to power systems engineering. Limits: comparisons across workloads are difficult.

13Questions

Questions and answers.

What is a supercomputer?
A computer system with very high processing capability, typically thousands of linked processors, used for large simulations and data analysis.
What does the TOP500 measure?
The sustained performance of systems on the LINPACK benchmark, which solves a dense system of linear equations, published twice a year.
Why are GPUs used in HPC?
Because they perform many calculations in parallel efficiently, which suits simulations and AI, though existing codes must be adapted to use them.
Will cloud computing replace supercomputers?
For many workloads, cloud is a good fit. Tightly coupled simulations that need fast interconnects still tend to run best on dedicated systems, although the boundary is shifting.
Why do AI and simulation compete for capacity?
Both need large amounts of computing, but they favour different hardware balances. Centres must decide how to serve both within limited budgets and power.
Does the platform publish rankings of computing capacity?
No. It publishes methods for describing capacity, need and dependency.
Data and Compute

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