When your MacBook's CPU works overtime, its cooling fan kicks in to dissipate the heat. To see which apps are using the most CPU resources, open Activity Monitor and click on the CPU tab. In my experience, the usual suspect at or near the top of the list using the highest percentage of the CPU is Google Chrome Helper and Google Chrome. If this also describes your experience, it may be time to switch to Safari or another browser.
I also find the cooling fan spins less frequently when my MacBook Pro isn't sitting in direct sunlight. When the sun hits my kitchen table in the morning, it's time to take my coffee and MacBook to my office. Apple recommends keeping your MacBook in a spot that's between 50 and 95 degrees Fahrenheit (10-35 degrees Celsius).
There is a chance that the reason your MacBook is overheating is there's something wrong with the cooling fan itself. Baked into your Mac is a hardware diagnostic tool. If it was made prior to June 2013, you'll use the Apple Hardware Test. After that date, you'll use Apple Diagnostics.
Sometimes you need to get under the hood. Get yourself a tiny Phillips-head screwdriver and you can remove the bottom panel of your MacBook to clean out any dirt, dust and grime that may have collected over the years. Use a can of compressed air to blow away any debris or use a lint-free cloth to wipe it away. Pay particular attention to the cooling fan itself and its vents, along with the entire back edge of your MacBook. The goal here is clean passageways for maximum airflow.
Disable Login Items. These are applications that automatically start when you log in to your MacBook. Too many applications running simultaneously can cause your MacBook to overheat. Click the "Apple" icon in the top left corner of the desktop on your MacBook, then select "System Preferences" from the drop-down menu. Click "Accounts," then click "Login Items." Select an item from the list that you don't want to start automatically, then click the "-" button. Repeat the process for any more items that you want to stop.
As it persists for a very long time, and it persists across restarts, it seems likely that your problem is caused by a hardware problem - namely lack of cooling. You do not describe which type of computer you have, but try looking at its cooling to see if it's working as intended. You might have a broken fan, lots of dust or similar.
2) Dust and Pet HairAnother killer of Macs is dust and pet hair. When I was doing a lot of consulting, one of the most common things I used to run into with any Mac with a built-in cooling fan was overheating due to an accumulation of dust and pet hair.
Bear in mind that any runaway process(es) can start to take over the CPU and result in a rising thermal load, which may trigger kernel_task to be used to lock those processes out and allow the CPU to cool. These include old favourites such as the Spotlight metadata demon mdworker, and plenty of extensions, startup items, etc. They can be tricky to identify without taking a look in the log, where they usually leave a trail of distress messages and good clues as to what is wrong.
Inside a PC, a stereo amplifier, or a smartphone, one red line runs through them all: The circuits inside generate heat, and something's got to keep things cool. The hardware used to keep PC components from overheating has undergone a revolution over the last decade, with once-rare liquid coolers now widely used in high-performance desktops and some cooling hardware playing a key cosmetic role in show-off gaming rigs and custom builds.
The processor cooling market is divided into two broad classes: air coolers and liquid coolers. Air coolers are the most common kind found in retail desktops; these are essentially metal heatsinks with fans that push air through their fins, accelerating the cooling process. Some of these are what are dubbed "stock coolers," cooling heatsink and fan assemblies provided by the two big chip makers (AMD and Intel) to complement their mainstream processors. (Most of AMD's stock line are dubbed Wraith coolers, while Intel's very newest stock coolers, on its 12th Generation "Alder Lake" chips, are dubbed the Laminar line.)
More exotic are water coolers, also known as closed-loop liquid coolers or all-in-one (AIO) CPU coolers. (An even more elite class of liquid coolers is custom-designed by each tube and joint rather than being a prefilled, premade system; we won't be covering that kind of advanced custom cooling hardware here.) AIO coolers, too, feature large metal constructs with fans, but those are actually radiators, mounted to the PC's case, through which the liquid flows in a circuit. The whole works differs significantly from an air cooler by using liquid-filled tubes and a pump to convey heat away from the CPU's "water block" (the assembly that sits atop the CPU and draws heat away), through the radiator for cooling, and back again in a loop flow.
It's a common mistake to assume that any water cooler is inherently better than any air cooler. Liquid coolers do have some undeniable advantages, but a specific cooler's design is critically important, and some air coolers perform better than some water coolers. Generally speaking, you can expect bigger coolers of either design to outperform smaller ones, simply because larger coolers generally have more metal within to spread out absorbed heat and can typically mount more or bigger fans. Both of these factors contribute to more efficient cooling.\
The size of your desktop system will end up playing a decisive role when picking a CPU cooler. For everyday use, the stock cooler or a slightly stepped-up air cooler will suffice, unless the CPU maker flat-out recommends a liquid cooling solution. (This is rare, and mostly applies only to upper-end chips like Intel's top Core i9 models and AMD's Ryzen 9 and Threadripper chips.)
For the best performance, but especially for system tweakers and CPU overclockers, you'll likely want the largest cooler that will fit inside your case, whether you go with an air or water solution. It's also worth noting that air coolers tend to benefit more from having extra case fans and strong ventilation to supplement the cooling action of the heatsink and the fan or fans mounted on the cooler. Water coolers have their radiators mounted to one of the case walls, and the radiator fans vent or pull air in or out of the system through the radiator, boosting case-wide ventilation and making these cooling systems less reliant on supplemental case fans.
With a firm handle on your system's size, case design, and motherboard and socket type, you're ready to choose a cooler. Here are the quick dozen we recommend, selected for the most common cooling scenarios.
Thermaltake's more premium TH120 ARGB 120mm water cooler packs a considerable amount of flair into a relatively small cooling device. For bling buffs, the system combines an addressable RGB (ARGB) fan with additional ARGB lights over the water block to illuminate the inside of your case and show off your hard-earned components. Noise production is rated at 28.2dBA, which makes it fairly quiet overall. The single fan is rated to move air at a rate of 59.3 cubic feet per minute. The big draw here, however, is the programmable lighting on the fan and block alike, which you can sync up with the rest of a custom build.
Noctua's background is in industrial and commercial fans, and its familiar maroon and beige fans for PC builders have long been a mark of quality for modders and upgraders in the know. The company's NH-D15 is well-known as one of the best-performing air coolers money can buy. This big, hulking cooler has two aluminum heatsinks perforated by six heat pipes, helping to spread out heat evenly from the CPU base plate. It's an ideal air cooling solution for a large PC case with a lot of vertical clearance.
When building a PC in a small-form-factor chassis such as compact Mini-ITX case, your CPU cooling options are significantly limited compared to those of a tower-style desktop. If you're creating or upgrading such a system and the case doesn't have room to add a water cooler, you might be tempted to give up and just rely on the stock cooler that your CPU came with. But even in these tight spaces, you can find better options. Thermal solutions built for this purpose are known as low-profile coolers, and Scythe's Shuriken 2 is an excellent one.
Measuring just 58mm tall, the Shuriken 2 is roughly the same size as one of AMD's or Intel's stock coolers, but it features a solid copper base plate and four heat pipes that help to transfer heat through its aluminum heatsink for better cooling performance. With its 92mm fan installed, the cooler has a relatively small physical footprint on the motherboard, too, as it was designed not to overhang the RAM slots on most boards. That's something many other air coolers struggle with. Its strictly trimmed dimensions keep the Scythe cooler out of the way when installing RAM and other components near the CPU socket.
The real issue arises when a system is thermal throttling. Not only will poor thermals cause CPU throttling, but it can also be an indicator that your PC is running too hot in general, and could suggest that the system cooling solution isn't sufficient. This could result in system temperatures rising too high under heavy workloads and force the processor to exceed its T-Junction rating (i.e. maximum safe temperature), which can lead to sudden and unexpected whole system shutdowns. And that's very bad indeed. For your system in the long run, and your sanity too.
Under the CPU section of HWMonitor, you should see three temperatures listed; the current, minimum, and maximum temperature of your CPU "Package". These temperatures will vary depending on which processor you have, as well as the efficacy of your cooling solution. The main thing to pay attention to though, is the current and maximum temperatures. If, whilst idle, your CPU already appears hotter than it should, then this is a good indicator that something is awry with your cooling solution. 2b1af7f3a8