v146 · capabilities · performance

Compute Pressure Pairing

Use the CPU Performance API for a static device tier, then combine it with live Compute Pressure states. The tier sets the quality ceiling; pressure and hysteresis decide how quickly the app steps down under load.

Feature detection checking...

CPU Performance API

Reading navigator.cpuPerformance...

Current spec surface: navigator.cpuPerformance, a coarse numeric tier where 1-4 increases capability and 0 means unknown.

Heuristic fallback

hardwareConcurrency + deviceMemory

Shown beside the real API so authors can see what the platform tier replaces when the API is available.

Applied app tier

Detecting...

This low / mid / high app tier selects the row family in the quality matrix. Override it below to test every floor.

Tier and pressure controls

Applied tier override

Raw pressure sample

Enable hysteresis: only apply a new pressure state after a 3-sample window agrees. This prevents fair/serious oscillation from changing video quality on every tick. Pause adaptation: keep collecting raw pressure samples, but freeze the effective recommendation until the app resumes.

Waiting for samples...

Current recommendation Detecting signals...

Media output preview

Video preset pending

Pressure history: raw samples and effective recommendation

Decision matrix - tier x pressure -> quality

Highlighted row matches the applied tier and the effective pressure state after hysteresis and pause rules.

CPU tier	Pressure state	Video quality	ML features	Particle budget	Background tasks
High	nominal	1080p 60fps	On, full model	2000	All enabled
High	fair	1080p 30fps	On, full model	1000	Throttled
High	serious	720p 30fps	On, lite model	400	Paused
High	critical	480p 15fps	Off	0	Paused
Mid	nominal	720p 30fps	On, lite model	500	Enabled
Mid	fair	720p 15fps	On, lite model	200	Throttled
Mid	serious	480p 15fps	Off	50	Paused
Mid	critical	360p 10fps	Off	0	Paused
Low	nominal	480p 15fps	Off	50	Throttled
Low	fair	360p 10fps	Off	0	Paused
Low	serious	240p 10fps	Off	0	Paused
Low	critical	Audio only	Off	0	Paused

const rawTier = typeof navigator.cpuPerformance === "number"
  ? navigator.cpuPerformance
  : 0;

const appTier = mapCpuPerformanceToAppTier(rawTier);

const observer = new PressureObserver((records) => {
  const rawPressure = records.at(-1).state;
  const effectivePressure = hysteresis.push(rawPressure);
  applyQualityPreset(appTier, effectivePressure);
});

try {
  await observer.observe("cpu", { sampleInterval: 1000 });
} catch (error) {
  // NotAllowedError can mean Permissions-Policy blocked "compute-pressure".
  useSimulationControls(error.name);
}

Decision matrix - tier x pressure -> quality

see also