Mac thermal throttling, explained

What thermal throttling actually is

Thermal throttling is your Mac protecting its own silicon. When the chip gets hot enough, macOS and the firmware reduce clock speed until the temperature comes back down. Less speed means less heat. The machine keeps working slowly instead of cooking itself.

Two things follow. Throttling is a safety feature, so there is no switch that turns it off and no app that removes it. And the temperature it starts at is fixed in the hardware, so nothing you install raises it.

What you can change is how long your Mac takes to get there. Heat leaves the chip through a heatsink and out of the case, and airflow is the one link in that chain a fan controls.

Throttling, or just a slow app?

Both feel the same: work that used to be fast is not fast anymore. The difference is the shape over time.

• Throttling has a warm-up. The first minute or two of a render runs at full speed, then the pace drops and stays down. An app that is slow is slow from the first frame.
• Throttling recovers when you stop. Let the machine idle for five minutes and the opening minute of the same job is quick again. A software problem does not care how long you waited.
• Throttling affects the whole machine. Window animations get choppy and unrelated apps feel sluggish. One misbehaving process leaves the rest of the system responsive.
• Throttling comes with heat you can feel. The deck above the chip and the air at the vents get hot before the slowdown arrives.

To confirm it, watch temperature and throughput together. If your export reports fewer frames per second than it started with while the chip sits near the top of its range and the fans still turn slowly, that is throttling.

Read the peak, not just the average

An instant reading tells you less than a short history. Breeze samples the CPU performance cores, the CPU efficiency cores, the GPU, and the wider SoC package every two seconds, keeps five minutes of history, and publishes a mean and a peak for each domain. The peak is what explains a slowdown you cannot otherwise account for: one hot performance core can pull clocks down while the package average still looks calm. Sensor coverage is discovered per machine, up to 42 sampled sensors.

Breeze has no throttling detector and does not claim one. It shows temperatures, fan speeds, and how both moved over the last few minutes. You read the shape and draw the conclusion.

Why Apple Silicon throttles while staying quiet

Apple Silicon changed the trade rather than removing it. The chips do far more work per watt, which is why a MacBook Pro can go a whole day of email in silence. Put an M4 Max under a sustained load and it still produces real heat, and it still has a temperature it will not pass.

The quiet is a deliberate choice in firmware. Every Mac with a fan runs a closed-loop controller that reads the chip’s sensors and writes a target speed to each fan several times a second, tuned for a quiet room. It lets the chip run hot for a long time before it spends any fan noise, because for most people silence is the better trade. The side effect: a long job can sit near the thermal limit while the fans are barely audible.

On a fanless machine there is no trade to make. Every Apple Silicon MacBook Air is passively cooled, so the chassis is its only heat path, and it throttles sooner than a Pro by design. No software changes that. Check which Macs have fans at all.

What actually helps

Roughly in order of payoff for effort:

1. Unblock the vents. A bed or a padded sleeve smothers the intake. A hard flat surface costs nothing and is often the whole problem.
2. Lift the machine. An inch of clearance gives the case cooler air to shed into. Any stand does this.
3. Cool the room. Ambient temperature sets the floor for everything downstream. The same Mac has less headroom in a hot room.
4. Find the load you did not ask for. A browser tab pinning a core or a container runtime idling hot adds heat all day. Activity Monitor, sorted by CPU, finds it.
5. Reduce what is plugged in. Fast charging while driving external displays adds heat inside the same enclosure as the chip.
6. Clear the dust. On a machine a few years old, a clogged heatsink is a real loss of airflow.

Some popular advice does nothing here. Apple Silicon has no SMC reset procedure, so the Intel-era key combination has nothing to invoke and a restart is the whole of the equivalent, and a passive aluminum slab under a laptop moves no air. There is also no clock or turbo setting to tune on these chips. The one real knob in the other direction is Low Power Mode, which trades speed for less heat on purpose.

Where manual fan control fits

A fan control app writes two values per fan: the mode, which selects firmware or manual control, and a target speed in RPM. That is the entire interface the hardware exposes.

The case where it earns its keep is pre-cooling. If you know a forty-minute export is coming, raise the fans before you start it, so the chip begins with a cooler heatsink and climbs toward its limit more slowly. macOS would reach that fan speed eventually. It just waits, and by then the clocks have already come down.

Breeze’s manual mode is one fixed target RPM per fan. There is no curve editor and no temperature-driven automation, and it never changes a fan speed on its own. Every speed is clamped to the minimum and maximum the fan itself reports, re-read before each write. It needs an Apple Silicon Mac on macOS 15 Sequoia or later. The setup is covered in detail here.

Breeze does offer one piece of feedback: it derives a recommended fan fraction from your current temperature, ramping between 62 °C and 95 °C, and tints the slider redder as your setting falls further below it. It only warns, and your number stays your number.

Handing control back is automatic. While a fan is manual, Breeze checks in with its privileged helper continuously, and if those check-ins stop for thirty seconds the helper restores automatic control on its own. Quitting does the same, and so does a helper shutdown. Fans come back under firmware control after a reboot or a power loss.

All the monitoring is free forever: every temperature, fan RPM, the per-sensor heatmap, and a menu bar item that can show a rolling graph, CPU temperature, GPU temperature, fan RPM, or nothing at all. The $12.99 one-time purchase unlocks manual fan control on up to 3 Macs.

What fan control will not fix

Worth being explicit about.

• It will not raise your thermal limit. The temperature at which macOS slows the chip is not adjustable. Faster fans buy you time before you reach that number, or keep you under it.
• It will not push a fan past its maximum. The ceiling belongs to the hardware.
• It will not help a fanless Mac. There is nothing to write to on an Air.
• It will not speed up work that was never thermally limited. If your build is waiting on a single-threaded step or a slow disk, cooler silicon changes nothing.
• It will not promise you a number. Whether higher fan speeds recover real performance depends on your model and your workload.

That last point is why the readouts cost nothing. Watch a real workload for a week and see whether your Mac is out of thermal headroom or just running a slow app. If it is heat, you have a lever. The FAQs cover the safety limits around pulling it.