Mac overheating — what to actually fix

A Mac that’s “running hot” usually isn’t overheating — it’s just doing work and the chassis is doing its job. Genuine overheating is different: the chip is at its thermal limit, performance has dropped, and the fans (if there are any) are at maximum. That’s the case worth fixing.

How to tell the difference

A Mac is genuinely overheating when:

• CPU die temperature is sustained above 95C
• pmset -g thermlog shows CPU_Speed_Limit below 100
• Fan speed is at or near maximum and not dropping
• Performance has noticeably collapsed (app launches feel like swimming through syrup)

A warm chassis with normal performance and fans not at max is not overheating. It’s an aluminium case getting rid of heat — which is the whole point.

Read the actual numbers

1. Run sudo powermetrics --samplers smc -i 1000 -n 1 in Terminal. Look for "CPU die temperature."
2. Run pmset -g thermlog and leave it for a few minutes. If you see CPU_Speed_Limit = 80 (or any number under 100), the system is throttling.
3. Check fan RPM in the same powermetrics output. At max RPM with high temp = cooling is at its limit.
4. Check load. Activity Monitor's CPU tab — is there something legitimately heavy running, or is the chip hot at idle?

What actually helps

In order of effectiveness:

• Unblock vents. Most Macs (especially MacBook Pro) take air in from the bottom edge or sides. A laptop on a bed, cushion, or in a sleeve blocks airflow. Move to a hard surface.
• Stop the workload. If a render or build is running, the chip is going to be hot. Pause it, let temps fall, then continue.
• Reduce ambient temperature. A 30C room makes everything harder. AC or fan helps.
• Lift the back edge. Even half an inch of lift improves airflow noticeably.
• Quit GPU-heavy apps. Video editors, games, and ML tools heat the SoC fast.
• Check for runaway processes. A 100% CPU process you didn’t intend is making the heat for nothing.

What doesn’t help

• Resetting SMC on Apple Silicon — there’s no user-resettable SMC. On Intel it can occasionally help with fan curve issues.
• Apps that “boost” fan speed — useful sometimes, but most overheating is airflow, not fan policy.
• Compressed air on vents — does help if dust has accumulated, especially on 3+ year old Macs.

Long-term causes

If your Mac is consistently hot at light loads, look for:

• A stuck launch agent or daemon (check Activity Monitor)
• A failing battery that’s drawing more power than it should
• Dust in the fans (genuine on older Macs)
• A worn-out thermal paste interface (rare; usually needs service)

Watching for throttling

The moment performance drops because of heat is the moment you want to know — not 20 minutes later. Beacon shows CPU temperature, fan RPM, and CPU load in the menubar, so you can see throttling as it starts. $14.99 lifetime. Download Beacon if you want that signal in front of you.

Real overheating is rare on a healthy Mac in normal conditions. When it happens, the fix is almost always airflow or workload — not the Mac itself.