Cooling · up to 5 minutes

Does it still run this fast in minute four?

Every Mac is quick for ten seconds. This runs a heavy shader on the GPU and watches whether the machine holds its speed as it warms up — a failed fan or dried-out thermal paste starts strong and falls away, and that decay is the only cooling fault a web page can honestly detect.

Before you start: plug the charger in and turn Low Power Mode off. On battery, macOS throttles hard on purpose — a perfectly healthy Mac will fail this test if you run it unplugged.

How long to run it

Speed now

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Frame cost

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Elapsed

0s / 300s

Start the test to record a trace

This model has no fan, so it will get genuinely warm and some slowdown is normal and expected. What matters is whether the line falls off a cliff or settles onto a plateau.

Is the “silicon lottery” real on Apple Silicon?

Mostly no, and it is worth knowing why before you pay extra for a “good one”. On desktop PC chips the lottery is real because you control the clock speed and the voltage, so an individual chip decides how far you can push it. Apple Silicon gives you neither. The clocks are fixed in firmware, there is no overclocking and no undervolting, and two healthy MacBooks of the same model perform within a couple of per cent of each other from cold.

Manufacturing variation is real, but Apple handles it by binning: a chip that misses the mark is sold as a lower-core-count part. That is the difference between the 8-core and 10-core M1 Pro. It shows up as a different product on the price list, not as a hidden lottery inside one.

What genuinely varies between two second-hand machines of the same model — sometimes by a lot — is how much speed they keep once hot. That is set by thermal paste, fan wear, dust in the vents, a swollen battery and whether it is plugged in. It is condition rather than luck, it is what this page measures, and unlike the chip lottery it is something you can actually negotiate over.

What this test cannot tell you

No web page can read a Mac's temperature sensors or fan speed — no operating system exposes them to a browser. Any site claiming to show you a temperature is making it up. Reading them natively needs an admin password, which nobody should type into a stranger's Mac. This measures the one thing it honestly can: whether the machine still runs as fast after several minutes of load as it did at the start.

A run under 120 seconds is reported as inconclusive on purpose. A Mac with a completely dead fan holds full speed for the first half-minute, so a short test would tell you it passed.

The workload is sized to this machine before the clock starts, because a load a fast Mac shrugs off would sit at the screen's refresh rate and measure nothing at all. That calibration is why the first few seconds show “calibrating”.

The verdict here is derived from the measurement rather than left to you to judge, which is why this page has no Pass and Fail buttons.

Worth buying alongside it

Warranty-backed alternatives and the accessories most Macs arrive missing

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