Glossary/Benchmark/Peak vs sustained performance

Peak vs sustained performance

Peak 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.

Also known as burst performance, steady-state performance

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 GPU raster load at a fixed resolution reporting frame rate, pacing and decay; and a path tracer reporting samples per second. The paragraphs below say which metric carries this term.

Peak is a marketing-friendly number. It is real (the machine genuinely did that, briefly), but it describes a state the system can hold for seconds. Sustained is what governs every task longer than a menu animation: exports, compiles, gaming sessions, model training.

The gap is a property of the whole system rather than the chip. The same processor shows a small gap in a well-cooled tower and a very large gap in a thin laptop. That is why identical spec sheets produce different experiences and why a single headline score cannot capture a machine.

SystemCheck reports both sides. The boost step shows how far the early peak region falls to the level the machine settles at, and the decay figure shows what it loses after that, which is the number that actually describes what your machine is like to use. A report showing high peak and steep decay is exactly the machine that benchmarks well and disappoints in practice.

Related terms

Sustained clockSustained clock is the frequency a processor settles at once the system reaches thermal and power equilibrium under continuous load.Read more Thermal decayThermal decay is the measurable fall in performance during a sustained load after the boost ends and the system settles, as it heats and hits its limits.Read more Sustained loadA 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.Read more Boost clockBoost clock is the highest frequency a CPU will reach opportunistically on a light thread count when thermal and power headroom allow.Read more 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 more

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