Diagnose
A throttling test that names the kind. Power limit or heat, not just a percentage.
Throttling is the chip stepping its clock down to stay inside a limit. Which limit is the whole question, and it is written in the shape of the curve.
What the report tells you
Three figures, each with its reading.
Decay
%
Throughput lost after the boost ends, from the level the machine settled at to the end of the run, on a curve sampled four times a second.
Kind
power / thermal
A single step is consistent with a power or current limit. A slide is consistent with a thermal limit. The report states its confidence and the measurement's noise floor, and a sensor tool confirms which.
Settled level
% of peak
On a deep run, where the chip ends up and how stable that level is across three windows.
The diagnosis
The shape of the curve, read for your case.
01A single step down
Consistent with power-limit throttling as the boost window closes. Adjustable in the BIOS or the vendor's tool; a sensor tool confirms it.
02A steady slide
Consistent with thermal throttling, the chip stepping down as it heats; a sensor tool confirms it. Cooling changes this curve.
03Held
No throttling within the run. On a standard run that means forty-five seconds; if you need longer, the deep run holds for three minutes.
Every class comes with a stated confidence and the measurement’s own noise floor. How the shape is read
Where a browser stops
What it cannot tell you.
- No clock speed: the browser measures throughput, so the report shows the effect of a clock change without the megahertz.
- No temperature: thermal throttling is inferred from the shape, never read from a sensor.
- Browsers round the core count and coarsen timers; the methodology page states the exact resolution used.
Which run
Standard, 3 minutes.
Forty-five seconds catches a boost timer expiring and the onset of a slide. Choose the deep run when the question is where the chip settles.
All three kinds are free. The choice is on the set-up screen.
Questions
Asked in these words.
- How do I test if my CPU is throttling?
- Run a sustained all-core load and watch throughput over time rather than a single score. If it keeps falling after its boost ends and it settles, that is consistent with throttling; a short boost and one step down early in the run is normal and shown separately as the boost step. The shape of the fall points toward a power limit or toward heat, and a sensor tool confirms which. This test does exactly that in a browser tab.
- What is the difference between power-limit and thermal throttling?
- A power limit is a wattage or current ceiling set in firmware: the chip drops to it in one step once its boost window closes. Thermal throttling is the chip stepping down progressively as its temperature rises: a slide. The fixes are different, which is why the report names the kind.
- Is 10% decay bad?
- Under about 8% is ordinary settling. Around 10% is a mild loss after the boost and is common on laptops. A short boost and one step down early in the run is not part of the figure. Above 15% with a sliding shape is consistent with cooling being the limit, and a sensor tool confirms which. The report puts the figure next to the shape so the number is read correctly.