It’s not uncommon for Macs to run a bit warm or have their fans spin up from time to time. But if your Mac is getting uncomfortably or worryingly hot, or the fans are revving up to a distracting degree, there are some steps you can take to cool things down and quiet the fans.
Quick Answers
Why do Macs get hot?
Macs generate heat from their internal components like the CPU, GPU, RAM, and storage drives. More intensive tasks make the components work harder and heat up more. The metal chassis absorbs and spreads out some of this heat.
Why do the fans get loud?
The fans spin faster to try to cool down the hot internal components. Faster fan speeds make more noise. Updated software, dust buildup, old thermal paste, and blocked vents can all cause fans to work harder than necessary.
How can I lower the temperature?
Improve airflow by cleaning dust from vents, elevate the Mac, use a laptop stand, point a fan at it, or try a cooling pad. Quit resource-intensive apps when not needed. Update to the latest macOS and apps. Replace old thermal paste. Consider adding more RAM or upgrading components if necessary.
How can I quiet the fans?
Update software, apps, and macOS to their latest versions. Clean dust buildup that forces fans to work harder. Use apps to control fan speeds. Replace worn-out fans. Consider upgrading components if fans are ramping up during light use. Check Activity Monitor for apps hogging resources.
Common Causes of Heat Generation
There are a few common culprits that can cause Macs to run hot and ramp up the fans:
Processor-Intensive Tasks
The CPU (central processing unit) and GPU (graphics processing unit) produce the most heat in your Mac. Things like 3D gaming, video editing, rendering, programming, simulations, virtualization software, and heavy multitasking put a lot of demand on these components and can quickly heat up your system.
Even lighter tasks like web browsing with multiple tabs open can warm up a Mac over time. The system is designed to dissipate heat from moderate use like this, but it’s normal for the aluminum unibody chassis to get moderately warm.
Insufficient Cooling
Dust buildup in the internal fans and vents can reduce airflow and the Mac’s ability to dissipate heat. This forces the fans to spin faster to try to cool things down. Old thermal paste between the CPU/GPU and the heat sink can also become inefficient at transferring heat.
Tight spaces or blocking vents can further restrict airflow. Using a laptop on a bed or soft surface can completely smother the bottom vents. Tower models pulled out from a desk can recirculate hot exhaust air if the back vents are blocked.
Software Issues
Apps with memory leaks, software bugs, or inefficient coding can use more resources than necessary, which heats up components. Running outdated OS and software versions that aren’t optimized for your Mac can lead to subpar performance. Malware and crypto-mining viruses in the background also tax the system resources.
Weak Hardware Components
If the CPU, GPU, RAM, power supply, and cooling system aren’t robust enough for a workload, they’ll run closer to their limits. This can cause overheating, throttling performance to compensate, and loud fan noise. Upgrading components like adding more RAM can help improve performance and reduce heat and fan speeds.
Short-Term Solutions
Here are some quick fixes you can try to cool down an overheated Mac and reduce loud fan noise:
1. Quit Unnecessary Apps
Quit any apps and browser windows you aren’t actively using. This reduces workload and CPU/GPU usage. Use Activity Monitor to identify processes hogging resources.
2. Improve Airflow
Make sure your Mac has open space around it for ventilation. Don’t block any vents. Position fans to blow air at hot spots. Use a laptop stand or cooling pad to elevate it.
3. Clean Out Dust
Use compressed air to blow out dust from the ventilation ports, fans, and heat sinks. This removes insulation keeping components hot.
4. Restart Your Mac
A reboot gives the OS a fresh start, clears memory, and stops any runaway processes. Your Mac will run cooler after a restart.
5. Avoid Intensive Tasks
Don’t game, render video, mine cryptocurrency, etc. while trying to keep your Mac cool. Stick to lighter tasks like web browsing and office work.
6. Use Cooling Software
Apps like Macs Fan Control let you adjust fan speeds. Lower speeds reduce noise but may compromise cooling. Only use when necessary.
Long-Term Solutions
For more significant and lasting cooling improvements and noise reduction, try these long-term solutions:
Update Software
Make sure macOS, apps, browsers, plugins, drivers, and firmware are up to date. Newer versions add optimizations and fix bugs that can cause performance issues.
Upgrade Hardware
Adding RAM can improve performance and reduce heat in some cases. Replacing an old mechanical drive with an SSD also runs cooler. Consider upgrading CPU, GPU, power supply, and cooling system if necessary.
Improve Airflow
Use laptop stands, external fans, and cooling pads. Elevate a laptop to completely open the vents. Ensure space around a tower Mac. Clean dust routinely with compressed air. Replace thermal paste every few years.
Check for Malware
Malware and crypto-mining software can secretly overload resources in the background. Run a scan to remove any unwanted hitchhikers.
Replace Worn Components
Old thermal paste dries out over time. Replace it to restore heat transfer between chips and heatsinks. Fans also wear out and become noisier. Replacing them restores quieter cooling.
Use Quieter Fans
Some third-party and upgraded aftermarket fans offer better noise-to-airflow ratios. Noctua, for example, makes whisper-quiet fans. Replacing stock fans can significantly lower noise levels.
Repaste the CPU and GPU
Replacing dried-out thermal paste between the CPU/GPU and heat sink improves heat transfer and allows the fans to run slower. Use high-quality thermal paste like Arctic Silver or Thermal Grizzly.
Normal Operating Temperatures
Macs are designed to withstand fairly high temperatures from normal operation. Here are the approximate normal operating ranges:
MacBook Pro
– Idle CPU: 40°C – 60°C
– Load CPU: 80°C – 100°C
– GPU: Around 10°C higher than CPU
– Battery/Outer Case: 0°C – 45°C
MacBook Air
– Idle CPU: 40°C – 60°C
– Load CPU: 80°C – 90°C
– Outer Case: 0°C – 45°C
iMac
– Idle CPU: 40°C – 50°C
– Load CPU: 80°C – 90°C
– GPU: Around 10° higher than CPU
Mac Pro
– Idle CPU: 35°C – 50°C
– Load CPU: 60°C – 90°C
– GPU: Around 10°C higher than CPU
– Outer Case: 25°C – 45°C
Mac Mini
– Idle CPU: 35°C – 50°C
– Load CPU: 70°C – 90°C
– Outer Case: 25°C – 45°C
So temperatures in those ranges are generally nothing to worry about for most tasks. Sustained temperatures over 90°C – 100°C can start to throttle performance and cause concern.
When to Be Concerned
Here are some signs that overheating may be a more serious issue:
Fans Constantly Running Fast
Fans that ramp up to high speeds frequently or constantly even during light use often indicate an airflow blockage, dusty heatsinks, failed fan, or misapplied thermal paste.
Throttling Performance
Prolonged temperatures near 100°C will cause Macs to throttle down processing speeds to try to cool down. This hampers performance.
Shutdowns or Crashes
Excessive heat can cause full system shutdowns, freezes, blue screens, graphical glitches, and application crashes. This indicates a component is overheating.
Burnt Smell
A smell like burning plastic could mean dust has completely blocked airflow or a fan has failed and a component is burning out. This requires immediate action.
Loud Fan Noise
Fans that are loud enough to make it hard to concentrate usually indicate inadequate cooling, obstructed vents, failing fans, or components generating too much heat for the cooling system to keep up.
Abnormally High Temperatures
Idle CPU temps consistently higher than 90°C or load temps near 110°C+ signal that cooling is insufficient for the hardware configuration and workload.
If you notice any of these warning signs, consider taking your Mac to Apple or an authorized service provider for inspection just to be safe. An overheating CPU or component failure can occur in extreme cases.
How to Check Mac Temperatures
To get a readout of your Mac’s temperature sensors, you have a few options:
1. Terminal
Open the Terminal app and type:
“`
sudo powermetrics –samplers smc | grep -i “CPU die temperature”
“`
This will display the CPU die temperature. Type Control + C to exit.
2. Activity Monitor
The CPU tab in Activity Monitor shows CPU usage, frequencies, power, and temperature readings across cores.
3. Third-party Apps
Apps like iStat Menus, TG Pro, and Macs Fan Control show temperatures, fan speeds, clock speeds, loads, and thermal conditions. Some can log data.
Example Temperature Readings
| Component | Idle Temp | Load Temp |
|---|---|---|
| CPU | 45°C | 82°C |
| GPU | 50°C | 92°C |
| SSD | 30°C | 45°C |
Choosing a Cooling Solution
If your Mac frequently runs hot or the fans are distractingly loud during normal use, adding some type of cooling solution can help:
Laptop Cooling Pads
Pads with built-in fans that sit beneath a laptop blow cool air into the vents and raise it off flat surfaces that can block airflow. Models from Tree New Bee, Havit, and OtterBox start around $30.
Laptop Stands
Stands like the popular Rain Design mStand and Griffin Elevator hold laptops off tables at an angle to improve airflow. Some have large fans or radiators built in. Prices range from $20 to $60+.
External Fans
Small desk fans or mini personal fans can direct a stream of cool air at hotspots on a laptop, iMac chin, or Mac Pro case. Brands like Honeywell and Vornado make quality options.
Case Mods
DIY modifications like mounting extra case fans, custom liquid cooling loops, or ventilation holes and mesh can enhance airflow and cooling in tower Macs like the Mac Pro and Mac Studio.
Third-party Heatsinks
Larger high-performance heatsinks from brands like OWC help dissipate heat from components like the CPU and GPU more efficiently so fans don’t have to work as hard.
Conclusion
All Macs will generate varying amounts of heat and fan noise during normal operation as a byproduct of their high-performance components. But excessive heat and loud fans can negatively impact performance and usability over time.
By understanding what causes Macs to overheat and become noisy, and using tools to monitor temperatures, you can take steps to keep your system running optimally. Improvements like cleaning dust, updating software, adding cooling accessories, upgrading components, and repasting the CPU and GPU can go a long way towards running your Mac coolly and quietly.