Quick answer
What this guide helps you determine
Learn how refresh rate relates to frame intervals and why requestAnimationFrame provides an estimate.
Begin with the observable browser result, repeat it under the same conditions, and change one connection, setting or application at a time. A browser result narrows likely causes but does not certify hardware or decide a repair.
Scope of this check
Refresh rate is how often a display updates per second, expressed in hertz. A browser can estimate presentation intervals with requestAnimationFrame, but the result is influenced by visibility, compositor scheduling, variable refresh, power mode and workload.
Step-by-step method
- Keep the browser window entirely on the display being checked and leave the tab visible. Close heavy animation or recording tasks, begin the estimate and allow a warm-up period before reading the stable range.
- Repeat several samples and compare the operating-system display setting. If the monitor supports multiple modes, change only that setting, confirm the display remains active, and run the same browser sample again.
- For variable-refresh systems, expect intervals to change with workload and browser behavior. Use the operating-system panel and monitor documentation as the authoritative configured mode; use the web result as an observation of this session.
What to check first
Use these checkpoints to keep the comparison focused. Record the visible behavior rather than assigning a fault label too early.
- Keep the tab foregrounded
- Allow warm-up before measuring
- Treat the value as browser-based evidence
How to read what you see
| Observation | What it can suggest | Useful next check |
|---|---|---|
| Samples cluster near the configured mode | Browser animation delivery is broadly consistent with that mode. | Record the range and display setting. |
| Estimate halves in a background or busy tab | Throttling or missed frames affect the browser measurement. | Foreground the tab and reduce load. |
| OS shows 60 Hz on a high-refresh monitor | The higher mode may not be selected or supported by the current cable/resolution. | Review display settings, port and cable specifications. |
Common mistakes to avoid
- Do not call a web estimate a calibrated refresh measurement.
- Do not change to an unsupported mode without a recovery plan.
- Do not compare samples from different displays with the window spanning both.
Build evidence another person can use
Write down the exact action, visible result and whether it repeats. Include the browser family, operating-system family, connection type and the single comparison that changed the result. Quote the observation directly—for example, “Samples cluster near the configured mode”—then add where it occurred and which comparison changed it.
Change one condition per comparison and return settings that have no effect. Follow model-specific manufacturer instructions before firmware changes, cleaning, disassembly or warranty action.
When to seek qualified support
If the same problem remains in multiple applications and on another compatible connection or computer, collect the repeatable observations and contact the manufacturer or a qualified technician. Stop using equipment that is physically damaged, unusually hot, wet, sparking or unsafe. Device Test Bench cannot inspect electrical condition or make a repair decision.
Privacy during testing
Our public tests process key events, pointer values, media streams and controller input locally. Do not send private recordings, complete typed text or device identifiers when asking for help. A short description of the behavior, browser and page URL is normally enough.
Questions readers ask
Why does 60 Hz appear as 59.9?
Timing standards, clock tolerances and measurement rounding can produce nearby fractional values.
Can a browser prove variable refresh is working?
Not reliably by itself. It observes frame callbacks, not the complete display link and panel behavior.
Primary technical references
The following specifications define the browser APIs discussed in this guide. They are primary web-platform references, not product repair manuals.