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Glossary/Benchmark/Sustained load

Sustained load

A sustained load is a workload held long enough for the system to reach thermal and power equilibrium, revealing real behaviour rather than a boost snapshot.

Also known as continuous load, long-duration load

Measured by SystemCheck

Part of the four-stage run: a 60-second sustained CPU load reporting throughput, decay and consistency; a memory stage reporting bandwidth and latency; a calibrated GPU raster load reporting frame time, pacing and decay; and a path tracer reporting samples per second. The paragraphs below say which metric carries this term.

Short bursts measure a machine in an unrepresentative state: cool heatsink, full short-duration power budget, no accumulated case heat. Sustained loads run past that transient into the region where the machine will spend the entirety of a real work session.

How long is long enough depends on thermal mass. Laptops and small-form-factor systems reach equilibrium in well under a minute. Large air and liquid coolers can take five to fifteen minutes. Any duration is a compromise between fidelity and how long a user will actually sit still for the test.

SystemCheck runs a 45-second sustained multi-core CPU load plus sustained GPU raster and path-tracing stages, for roughly three minutes total. That is enough to expose throttling on the systems where it matters most (thin laptops, compact builds, and dusty machines) while remaining a test people finish. On a large tower cooler, read a low decay figure as good behaviour through 45 seconds rather than as a guarantee for an hour.

Related terms

Heat soakHeat soak is the state reached when a cooler and case have absorbed all the heat they can buffer, so component temperature depends only on airflow and ambient.Read moreThermal decayThermal decay is the measurable fall in performance from the start of a sustained load to its steady state as the system heats and hits its limits.Read morePeak vs sustained performancePeak performance is the best a system does in a short burst; sustained performance is what it holds at equilibrium, and the gap can exceed 30% on laptops.Read moreBurn-in testA burn-in test runs a system at heavy load for hours to expose early-life component failures and validate cooling and power delivery on a new build.Read moreStress test vs benchmarkA stress test pushes a system to its limits to find instability; a benchmark measures performance under a controlled workload to produce a comparable score.Read more
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