As computers have become more compact and powerful simultaneously, dissipating all the heat generated by the processor and graphics chipset is a major challenge. Desktops generally have enough room for robust cooling systems which can stop the computer getting too hot under almost any conditions. Phones and tablets are so low powered that not much heat can be generated anyway. Laptops however can get the worst of both worlds — they can be powerful computers but are packed into such a tight form factor that they can overheat easily. This is especially true when it comes to MacBooks, which is what this article will focus on, due Apple’s design priority of sleek form factors. So read on to find out how to stop your MacBook from overheating!
If you can hear your MacBook’s fans then chances are it’s overheating. To confirm the core temperature however you will need to download a third party application: iStat Menus or SMC Fan Control. The former should work on any modern Mac and has a very polished and powerful interface, however requires a license to be purchased after the 14 day free trial. SMC Fan Control is more basic and compatibility is hit-and-miss with newer Macs, however unlike iStat Menus it is freeware.
Once you have downloaded and installed either iStat Menus or SMC Fan Control, you will be able to see your MacBook’s core temperature in the menu bar. If the temperature is below about 70C then you should certainly not be hearing the fans spin. In the case that the fans are loud under sub-70C temperatures then there may be an issue with your Mac’s SMC. You can find Apple’s instructions here to reset the SMC for any type of Mac you may have.
If your MacBook’s core temperature is in the 80C, 90C to 100C range then you can expect the fan(s) to spin up to the point you can hear them. This is perfectly normal if you are performing intensive tasks such as video editing, emulation or gaming. However if you are not doing anything intensive on your Mac, or if the computer remains hot even when doing nothing at all, then there could be an application or process taxing system resources in the background.
A likely cause of this is Spotlight indexing. Periodically Spotlight may perform an indexing on your Mac’s filesystem — although you may not notice anything this is intensive and can cause your Mac to heat up. Click on Spotlight in the menu bar and you will be able to see if it’s indexing. If this is the case then the heat issue should disappear after Spotlight finishes indexing. The time this takes depends on how much data you have stores on your Mac, however if you have waited a long time read this article for solutions to stop Spotlight from indexing.
If Spotlight is not indexing then open the Activity Monitor application and check the system load at the bottom of the window. The largest proportion of the system resources should be idle if your Mac is not doing anything.
The idle proportion being low indicates there is a process consuming most of your Mac’s resources. Sort the processes in Activity Monitor by % CPU and you will be able to see what processes these are. Solving the problem may be as simple as closing an offending application or restarting your computer, however if it persists you can search something like “XYZ process high CPU use Mac” on the Internet and will most likely be able to find a solution.
When checking Activity Monitor if you are finding that most resources are idle while your MacBook is hot and the fans are spinning, the issue will almost certainly be a lack of ventilation. Place your MacBook on a hard flat surface such as a desk and observe the core temperature. After a few minutes the fans should spin down as the temperature drops. Using your MacBook on cushions, carpet or in bed insulates the case and stops heat from escaping. If you are having overheating issues avoid these surfaces, and instead use hard flat surfaces. On your lap a hardcover book can be used to improve ventilation, or a laptop cooling pad could be purchased for even greater efficiency.
Keyboard protectors are often said to block the airflow on MacBooks. However no MacBook has ever vented air via the keyboard, so whether you use a keyboard protector or not will have little impact on the computer overheating.
What if your MacBook is still running hot when CPU use is low and the computer is on a flat surface? High ambient temperature could be a cause if the environment is especially hot (Apple recommends an ambient temp of no more than 35C). However if your MacBook is a year or more old the high temperature could be caused by dust trapped inside the case. To check this you will need to remove the cover underneath your MacBook — how this is done depends on which model and year your Mac is. Best way to find out is search on YouTube for how to remove the cover for whichever model/year of MacBook, as there are many video tutorials explaining the process. Some older MacBooks have the cover held on with regular Philips screws, while newer models require a special star screwdriver to remove them.