Do the model and state preflight first
- Open Smart Breeze and confirm it reports discovered fans for your Mac.
- Install the signed Smart Breeze app in /Applications and complete helper approval through Smart Breeze; do not keep duplicate app copies.
- Select System and confirm the dashboard reports macOS as the verified controller before beginning.
- Confirm temperature readings and both actual fan RPM values are available and plausible.
- Record whether the Mac is on its power adapter or battery. Each source has a different curve.
WarningStop if the preflight does not match
Smart Breeze enables Smart Boost, Max, Manual, and curve writes only where it discovers a complete fan topology. If controller ownership, fan topology, or readings are unavailable, stay in System and use Copy Diagnostics rather than continuing the procedure.
Capture a baseline you can reproduce
A curve edit is only interpretable against a consistent baseline. Start in System and run the task you actually care about long enough to include its warm-up and sustained phase. Use the same project, quality settings, window state, power source, and approximate room conditions each time. Do not mix a battery run with an adapter run and call the difference a curve result.
| Record | Why it belongs in the comparison |
|---|---|
| Selected sensor and live temperature | Shows which input would drive the curve and how it changes over time. |
| macOS thermal-pressure state | Adds system context that one private sensor number cannot provide by itself. |
| Actual fan RPM | Captures what the fans physically report, not only a requested target. |
| Workload phase and duration | Separates a short spike from a sustained thermal pattern. |
| Power source and power mode | Avoids attributing a power-policy difference to the curve. |
MethodWrite the question before moving a point
A testable question is specific: “Will an earlier middle-curve request change the sustained temperature trend while actual RPM continues to follow target?” “Make the Mac cooler” is too broad to identify which edit worked or whether a tradeoff was acceptable.
Edit the curve as a staged draft
- In the dashboard, choose Smart Boost and select Balanced, Performance, or Quiet Boost as the nearest starting shape.
- Select the sensor source: Any Sensor, CPU, GPU, or Battery. If the chosen category is unavailable, Build 37 labels and uses the hottest available fallback.
- Choose Customize Curve. Smart Breeze snapshots the current configuration and opens a draft; edits do not become the saved Custom profile until Apply.
- Move one temperature or percentage at a time. Add or remove points only when the shape cannot express the transition you need.
- Review hysteresis and cooldown, then apply the complete draft as one transaction.
- If the result is not useful, restore the previous committed curve rather than trying to remember every value.
| Build 37 validation rule | Purpose |
|---|---|
| 2–8 points | Keeps a curve defined without allowing an unbounded editor document. |
| 35–100 °C per point | Rejects out-of-range temperature inputs at the product boundary. |
| At least 3 °C between adjacent points | Prevents duplicate or nearly overlapping temperature steps. |
| 0–100% and nondecreasing | A hotter point cannot request a lower percentage than the preceding point. |
| Hysteresis 1–12 °C; cooldown 5–180 seconds | Constrains release behavior to finite supported settings. |
Percent is relative to each fan’s reported range. If a fan reports a 1,350 RPM minimum and 5,777 RPM maximum, a 50% curve value maps to about 3,564 RPM before Smart Breeze applies the session’s macOS baseline and nondecreasing-target rule. Do not copy an absolute RPM from a different Mac and assume the percentage is equivalent.
Treat adapter and battery as two tests
The profile editor exposes the curve for the Mac’s current power source. Build 37 saves independent adapter and battery points, then switches automatically when the power state changes. A complete custom profile therefore needs deliberate review in both states, even if you decide that one should remain identical to its preset.
- Finish and record the adapter draft while the power adapter is connected.
- Return to System before deliberately changing power state for a controlled comparison.
- Open the battery curve and make a separate decision; do not assume the adapter points were copied.
- Account for macOS power mode and normal workload changes when unplugged.
- Verify which curve is shown after reconnecting power before the next run.
NotePower mode is another variable
Apple power modes can change energy use, fan behavior, and performance on supported Macs. Keep the macOS power mode constant across A/B runs or record the change explicitly; otherwise the curve is not the only variable.
Verify the run, not just the graph
- Select the new Custom profile while Smart Boost is watching under System.
- Start the same workload from comparable initial conditions.
- Confirm the named sensor crosses the first point and the controller changes from macOS to Smart Breeze.
- Compare requested target with actual RPM. A momentary difference is expected; a persistent substantial mismatch is a reason to stop and capture diagnostics.
- Observe the temperature trend and thermal pressure through the sustained portion, not only one peak reading.
- End the workload and verify temperature remains below the release threshold for the cooldown, followed by a confirmed System handoff.
MethodChange one thing per run
Moving four points, changing the sensor, shortening cooldown, and switching macOS power mode creates an attractive graph but no useful attribution. Keep a simple run log and change one control at a time.
Know the stop and restore conditions
Choose System immediately if the dashboard cannot verify fan ownership, actual RPM persistently fails to approach a substantial target, temperature becomes unavailable, the helper reports an authorization or transport problem, or behavior differs from the written test. Copy Diagnostics before restarting so the state is preserved for investigation.
- Use Restore Previous Curve when the configuration is the problem.
- Use System when the current control session is the problem or you simply want macOS to resume normal policy.
- Do not use Max as a way to hide an unexplained target/readback mismatch.
- Run Apple Diagnostics when the Mac’s fans, ventilation, or thermal behavior suggests a hardware issue rather than a curve-choice issue.
If you are still deciding which control model fits the task, compare automatic curves, fixed RPM, and timed Max. If the open question is which temperature should drive the curve, use the sensor selection guide.
Sources
- Smart Breeze compatibility by exact Mac model (Smart Breeze)
- Smart Breeze helper installation and repair (Smart Breeze)
- Use Apple Diagnostics to test your Mac (Apple Support)
- Use power modes on your Mac (Apple Support)
More from the guides
Fan curvesMac fan curves: what the points actually controlLearn how a temperature-to-fan curve works on a Mac, how Smart Breeze maps each point to a bounded RPM target, and how Smart Boost returns control to macOS.
Fan curvesWhich Mac temperature sensor should control a fan curve?Choose Any Sensor, CPU, GPU, or Battery for a Smart Breeze fan curve by matching the sensor to a repeatable workload and checking fallback behavior.
Fan curvesThe best Mac fan curve is a method, not a presetBuild a defensible Mac fan curve with a System baseline, one-variable tests, separate power-source curves, and clear keep-or-reject criteria.Related docs: Install Smart Breeze, Troubleshooting, Safety model
Download the signed app, review compatibility, and keep System as the starting and fallback state. Open the download checklist