Macs that are too hot feel hard, are hot to the touch, and are often slow or unresponsive. Heat is very bad for computer hardware, so keeping things cool can help extend the life of your MacBook, iMac, or Mac Pro.
How To Tell When Your Mac Is Too Hot
There are a number of signs that show that your Mac is running very hot. The most obvious is that the Mac feels hot to the touch, especially on the bottom of the chassis if you have a MacBook.
When your Mac is hot, you should expect the fan to try to cool it down. This means you will hear enough fan noise when your engine is loading. Under extreme load, it’s not unusual for your Mac to sound like it’s about to take off.
The computer shouldn’t be too hot to touch, although certain processes might make it warm, especially if it’s the laptop you are using on your lap. Remember that heat is a normal part of your Mac’s operation, and a loud whirring fan means the machine is operating as usual in an attempt to cool itself.
What is not normal is a silent Mac hot, which can indicate that fans have failed. A loud cracking sound is also a red flag and usually occurs when the cushion on the cooling mechanism is working loosely.
You can also use a small application like smcFanControl to place a widget in the menu bar that displays how hot your Mac is running inside the case. In general, around 90ºc (194ºF) is not unusual for Macs under heavy loads, but you want to keep things under 95ºc (203ºF).
In the end, you don’t need to worry about cooling your Mac manually (though there are a number of things you can do to help). macOS will temporarily underclock your processor to reduce heat, a process known as thermal retarding. There are several things you can do to help reduce this.
Make sure your Mac can cool itself properly
You don’t need to do anything to heat up your Mac. If the ambient temperature is hot enough, your Mac will reflect by running the fan for longer and at a higher speed. If you are outside on a sunny day and feel warm, there’s a good chance your MacBook is too.
Look at the bottom and back of your Mac laptop, if you have one. This is where your engine takes and discharges water, and this ventilation is an important part of the cooling system. If your Mac can’t “breathe,” then the Mac won’t be able to cool either.
For example, the MacBook Pro sucks cold water at the bottom of the engine near the right and left edges of the chassis. This expels hot air from behind, behind the display hinges. If you block this vent, your Mac will heat up even under regular load.
Be careful when using your Mac on soft materials, such as your lap or bed. Sheets and clothing can easily interact with air intakes, so it’s best to place your MacBook on a sturdy surface. This can be a table, or it can be a wooden tray or ledger on the bed.
Laptop coolers (like this from Thermaltake) can help cool a MacBook that is struggling in the heat. This is in the form of a metal holder with integrated fans. The metal acts as a heatsink, helping to spread heat through conduction while the fan provides active cooling. You will need a backup USB port to use a cooler like this.
Beware of the Thirst Software
Central Processing Unit (CPU) is the brain of your computer. The more you overload the CPU by running applications, copying files, and doing many tasks, the more heat is generated. When heat builds up, the fan kicks in to disperse the heat.
You can withstand heat by avoiding processes that produce high loads, such as rendering videos or playing 3D games. Using lightweight alternatives for applications like Photoshop can certainly help too. Switching from a resource browser like Chrome back to Safari can help. Even remember to quit the heavyweight application when you are done with it can do wonders.
Sometimes, malicious processes end up consuming too much CPU for a long period of time. This could be due to a process that is very resource-intensive, or it could be because the application is crashing. If your fans have been spinning for a while and your Mac is slow or unresponsive, you should check the running processes using Activity Monitor.
Warning: We only recommend this if your Mac is slow, unresponsive, and too hot. Although you can’t immediately destroy anything by doing this (important system services will only restart themselves), you might feel more comfortable just restarting your Mac.
Launch the Activity Monitor on your Mac by searching for it with Spotlight, or by launching it under Applications> Utilities. Under the “CPU” tab is a list of processes that are currently running. Click on the “% CPU” column to arrange them in descending order, which will place the most tiring process at the top of the list.
If a process appears red or is followed by the “(Not responding)” label, then the process is stuck. You can wait a while to see if they return, or you can simply click the process, then use the “X” button at the top of the screen to turn off the process.
Sometimes, the application doesn’t crash enough but still uses more than a fair portion of CPU power. This often happens with tabs on web sites especially resource intensive. If you know you definitely don’t use tabs or apps for important things, you can select them and then use the “X” button to kill them.
Be careful not to kill any processes that you still use. It is normal for certain activities to use a lot of CPU power, for example when you make videos, run Automator scripts, install software updates, and so on. Before you kill a process, double check it’s not important before you do it.
Some processes are persistent, like “kernel_task” which is basically your operating system that does household tasks. If this process improves, chances are your computer is doing something important in the background. For a very stubborn process, you can always try restarting your Mac.
Your GPU May Also Be Wrong
While the CPU handles most of the computing tasks, the Graphical Processing Unit (GPU) handles the tasks more visually. GPUs are designed with different workloads in mind, and can offer a big boost in performance when it comes to 3D and 2D rendering.
This includes activities such as playing 3D games, rendering videos, manipulating 3D objects in applications such as Photoshop or Blender, and using some web technologies such as WebGL. Not all Macs have special graphics processors, especially low-end notebooks like MacBook Air and 13 “MacBook Pro.
There isn’t much you can do about hot GPUs other than avoiding activities that use your GPU. Remember, it’s very normal for your GPU to heat up under load, and for fans to improve significantly to deal with it.
The only thing you need to worry about is whether your GPU is too hot. This will cause problems with your computer around 3D and other GPU related tasks. You might get a restart and freeze randomly, or even see strange colors and glitchy graphics when trying to create a 3D environment.
If you see a problem like that, it might be a good idea to run some hardware diagnostics or order a machine to be fixed.
Fans that Continue to Rotate? Reset SMC
The System Management Controller (SMC) is responsible for managing aspects of your Mac including power, battery and charging, sensors and indicator lights, and thermal management features such as fans. Sometimes, the SMC needs to be reset, and one sign is that fans don’t want to be quiet.
This is different from the CPU or GPU that is being loaded. Fans that indicate this problem spin hard all the time, regardless of how hot or cold your engine is. On a MacBook, it must be clearly touched when the Mac isn’t hot enough to guarantee loud fan noise. On iMac or Mac Pro, you can download free apps like smcFanControl or premium apps like iStatMenus to monitor temperatures.
Resetting the SMC certainly can’t hurt your Mac, so it’s worth a try if this is a meeting problem. The instructions for doing that vary depending on your specific model. Find out what you need to do to reset your Mac’s SMC here.
Eliminate Dust Stacking by Cleaning Your Mac
If your computer is rather long on your teeth, it is possible that dust is starting to build up inside the chassis. The dust adheres to fans, heatsinks and other cooling components and stops it from working efficiently. Your engine will get hotter over time because of reduced air flow due to dust collection.
The answer to any old machine that runs hot for no reason is to clean it. You can do this by opening the engine, cleaning dust with compressed water, then resealing it.
Keep in mind that Apple computers have certain cooling systems and layout. It’s not difficult to find a cooling fan inside the MacBook, and the cleaning process is the same as other laptops. You can follow the general computer dust guide for your iMac, but you might be better off using something more specific.
iFixit is an excellent resource for this opportunity. Many iMac, Mac Pro, and even Mac mini models have guidance on how to open the chassis, clean the dust, replace parts and put them back together.
Remember: Static electricity kills a computer. Make sure you understand how to ground yourself if you are going to poke under the hood.
Important: Is your Mac Hot and Quiet?
If you have problems where your Mac is hot but the fan is not spinning, we first recommend that you reset your SMC as described in the “Playing Fans Permanently? Reset SMC” section above. If it fails, your cooling system may have been completely edited.
If this is the case, you should stop using the computer immediately and bring it in for repair. Using a Mac without adequate cooling can cause permanent damage. At the very least, your computer will be restarted randomly because various components reach temperatures that were never designed to operate.
Understand What Causes Hot Macs
By understanding why your Mac is hot, you can take steps to prevent it. Most of the time this involves killing several processes or moving from the bed to the table.
Software can cause your Mac to heat up, and can also cause your Mac to slow down as well. Learn how to fix an unresponsive Mac so that everything runs smoothly.