Sep 13, 2016 App Nap. When your app isn’t busy performing user-initiated work, the system may put your app in App Nap. App Nap conserves energy by regulating your app’s CPU usage, I/O, and timers. As soon as the user resumes interacting with your app, OS X switches it back to full speed. Nov 15, 2013 Mavericks makes it easy to see the top app or two that uses the most energy on your Mac with a quick Option-Click on the battery menubar icon, letting you.
Apple takes great strides to ensure that your Mac thermals run well within the hardware specifications automatically without consumer intervention. The goal for Apple is to give you the best possible performance while keeping the system as quiet as possible all whilst using the least amount of power. And they do a pretty decent job of it too. However, sometimes you may wish to forego the quiet for cool. Or perhaps forego the cool for quiet. You can take more direct control over your Mac's fan speeds with the Macs Fan Control app!
Why bother overriding the fans
If you are one to leave well enough alone, then this is not something you'd want to delve in to. As mentioned, Apple does its homework when it comes to what fans should run at what speeds for the amount of heat and power being produced and used. It ensures that your Mac being a MacBook, MacBook Pro or even a Mac Pro can function with decent capabilities while maintaining stability and safe operating temperatures.
That being said, even Apple is a prisoner to the hardware specs. If a CPU starts to run at too high of an operating temperature, it will have to throttle its frequency to a lower setting. This lowering of frequency allows the CPU to run less power and in turn run cooler thus lowing the operating temperature. This avoids damaging the CPU. However, the lowering of the frequency also lowers the performance capabilities of the CPU. Making it run your tasks slower as a result.
In order for the CPU to not throttle its frequency to a lower state, sufficient cooling must be available to avoid high operating temperatures. Sufficient cooling means faster fan speeds. Faster fan speeds means louder computers. Apple tends to configure its hardware towards quiet operations. Since the tendency is for quieter computers, that will also mean you'll have a tendency for throttling your CPU due to higher temperatures.
If you are on that doesn't care about fan noise and want 'ALL THE POWER' then running your fans at higher spec to keep temperatures lower for longer may be what you're looking for. And vice versa, if you want quiet operation for a long as possible, then limiting when your fans speed up or slow down may be in your best interest. But be warned!
Some warnings
Changing your fan speed can cause a minimum greater wear and tear on your components. Maybe unnecessarily so. At worst, you can completely destroy your hardware components if you allow temperatures to rise too greatly with adding sufficient cooling. So be aware that fiddling with your Macs designed specifications will indeed break warranty and can even break your Mac.
Macs Fan Control
If you think that you still want to go ahead and manually control your Mac fans, here's what to do.
- Download the Macs Fan application.
- Use Finder to navigate to your Downloads folder.
Drag the Macs Fan Control ** app to your **Applications folder.
- Double-click the Macs Fan Control app in Applications.
- Click Open.
You'll now see a list of Fans that you can manually override on the left and a list of current operation temperatures on the right. Let's for example decide that we want to make certain that our Mac gets the most amount of fresh cool air into the system. We can decide to override the settings for INTAKE and EXHAUST.
- Next to the EXHAUST section, click Custom.
- You can use the slider to manually set a constant fan speed at whatever you desire.
Or you can choose to set a Sensor-based value where given a certain temperature on a specific sensor one the system, the fan can start to increase speed and go to its maximum speed at yet another temperature for that same sensor. Here we choose Ambient temperature as our sensor. We left the temperature range as default.
- Click OK.
- Repeat the same steps from 1 to 4 but with the INTAKE fan.
You'll immediately hear a change in fan speed once you click OK. You can keep an eye on your sensor value to see if the change you applied makes a difference to your liking.
If you decide that you want these changes to persists after a reboot do the following.
- Click Preferences.
Check the Autostart minimized with system (recommended) box.
- Click Close.
See if the changes are worthwhile
Now you should monitor your system and the temperatures. Perform your normal tasks and see if the changes you made are 1) working like you envisioned and 2) worth the extra heat or sound emanating from your machine.
Final comments
I can make my system cool down a good 5 degrees celsius with my own custom changes but at a cost of considerably louder fan speeds. For my day to day task it's not worth it. But If I only enable my changes when I use CPU intensive tasks where I'd expect more fan noise, then for my it's worth the increase in noise. What about you? Any interest in controlling your Mac thermals? What do you do about it? Let us know in the comments!
macOS Catalina
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iMac (Retina 5K, 27-inch, 2019) | |||
|---|---|---|---|
27-inch Retina 5K display, 3.6GHz Intel 8-Core i9, 64GB 2666MHz DDR4 SDRAM, 3TB Fusion Drive, AMD Radeon Pro Vega 48 with 8GB memory | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
71W | 262W | 242 BTU/h | 895 BTU/h |
iMac (Retina 4K, 21.5-inch, 2019) | |||
|---|---|---|---|
21.5-inch Retina 4K display, 3.2GHz Intel 6-Core i7, 32GB 2666MHz DDR4 SDRAM, 1TB Solid State Drive, AMD Radeon Pro Vega 20 with 4GB memory | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
47W | 166W | 161 BTU/h | 568 BTU/h |
iMac (Retina 5K, 27-inch, 2017) | |||
|---|---|---|---|
27-inch Retina 5K display, 4.2GHz Intel Quad-Core i7, 64GB 2400MHz DDR4 SDRAM, 3TB Fusion Drive, AMD Radeon Pro 580 with 8192MB memory | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
71W | 217W | 242 BTU/h | 741 BTU/h |
iMac (Retina 4K, 21.5-inch, 2017) | |||
|---|---|---|---|
21.5-inch Retina 4K display, 3.6GHz Intel Quad-Core i7, 32GB 2400MHz DDR4 SDRAM, 512GB Solid State Drive, AMD Radeon Pro 560 with 4096MB memory | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
49W | 161W | 168 BTU/h | 550 BTU/h |
iMac (21.5-inch, 2017) | |||
|---|---|---|---|
21.5-inch display, 2.3GHz Intel Dual-Core i5, 16GB 2400MHz DDR4 SDRAM, 256GB Solid State Drive | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
33W | 74W | 113 BTU/h | 253 BTU/h |
iMac (Retina 5K, 27-inch, Late 2015) | |||
|---|---|---|---|
27-inch Retina 5K display, 4.0GHz Intel quad-core Core i7, 32GB 1866MHz DDR3L SDRAM, 3TB Fusion Drive, AMD Radeon R9 M390 with 2GB memory | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
63W | 240W | 215 BTU/h | 819 BTU/h |
iMac (Retina 4K, 21.5-inch, Late 2015) | |||
|---|---|---|---|
21.5-inch Retina 4K display, 3.3GHz Intel quad-core Core i7, 16GB 1866MHz LPDDR3 SDRAM, 2TB Fusion Drive | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
40W | 119W | 136 BTU/h | 406 BTU/h |
iMac (21.5-inch, Late 2015) | |||
|---|---|---|---|
21.5-inch display, 1.6GHz Intel dual-core Core i5, 16GB 1866MHz LPDDR3 SDRAM, 1TB Fusion Drive | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
33W | 58W | 113 BTU/h | 198 BTU/h |
iMac (Retina 5K, 27-inch, Mid 2015) | |||
|---|---|---|---|
27-inch display, 3.3GHz Intel Core i5, 32GB 1600MHz DDR3 SDRAM, 3TB Fusion Drive, AMD Radeon R9 M290 | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
70W | 197W | 239 BTU/h | 673 BTU/h |
iMac (27-inch, Late 2014) | |||
|---|---|---|---|
27-inch display, 4GHz Intel Core i7, 32GB 1600MHz DDR3 SDRAM, 3TB Fusion Drive, AMD Radeon R9 M295X with 4096MB memory | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
70W | 288W | 239 BTU/h | 983 BTU/h |
iMac (21.5-inch, Mid 2014) | |||
|---|---|---|---|
21.5-inch display, 1.4GHz Intel Core i5, 8GB 1600MHz DDR3 SDRAM, 500GB HDD, integrated graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
33W | 68W | 113 BTU/h | 232 BTU/h |
iMac (Late 2013) | |||
|---|---|---|---|
iMac (21.5-inch, Late 2013) | |||
21.5-inch display, 3.1GHz Intel Core i7, 16GB 1600MHz DDR3 SDRAM, 1TB Fusion Drive, NVIDIA GeForce GT 755M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
37W | 136W | 126 BTU/h | 463 BTU/h |
iMac (21.5-inch, Late 2013) | |||
|---|---|---|---|
21.5-inch display, 2.9GHz Intel Core i5, 8GB 1600MHz DDR3 SDRAM, 1TB Serial ATA Hard Drive, NVIDIA GeForce GT 750M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
37W | 94W | 127 BTU/h | 322 BTU/h |
iMac (21.5-inch, Late 2013) | |||
|---|---|---|---|
21.5-inch display, 2.7GHz Intel Core i5, 8GB 1600MHz DDR3 SDRAM, 1TB Serial ATA Hard Drive, Intel Iris Pro Graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
38W | 91W | 129 BTU/h | 311 BTU/h |
iMac (27-inch, Late 2013) | |||
|---|---|---|---|
27-inch display, 3.4GHz Intel Core i7, 32GB 1600MHz DDR3 SDRAM, 3TB Fusion Drive, NVIDIA GeForce GTX 775M | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
78W | 229W | 266 BTU/h | 782 BTU/h |
iMac (27-inch, Late 2013) | |||
|---|---|---|---|
27-inch display, 3.4GHz Intel Core i5, 8GB 1600MHz DDR3 SDRAM, 1TB Serial ATA Hard Drive, NVIDIA GeForce GTX 775M | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
80W | 214W | 274 BTU/h | 729 BTU/h |
iMac (27-inch, Late 2013) | |||
|---|---|---|---|
27-inch display, 3.2GHz Intel Core i5, 8GB 1600MHz DDR3 SDRAM, 1TB Serial ATA Hard Drive, NVIDIA GeForce GT 755M | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
78W | 180W | 268 BTU/h | 615 BTU/h |
iMac (21.5-inch, Late 2011) | |||
|---|---|---|---|
21.5-inch display, 3.1GHz Intel Core i3, 2GB 1333MHz DDR3 SDRAM - 2x2GB, 250GB Serial ATA hard drive, AMD Radeon HD 6750M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
80W | 101W | 273 BTU/h | 345 BTU/h |
iMac (21.5-inch, Mid 2011) | |||
|---|---|---|---|
21.5-inch display, 2.5GHz Intel Core i5, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 500GB Serial ATA hard drive, AMD Radeon HD 6750M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
81W | 106W | 276 BTU/h | 362 BTU/h |
Power Consumption Of Mac App Download
iMac (21.5-inch, Mid 2011) | |||
|---|---|---|---|
21.5-inch display, 2.7GHz Intel Core i5, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, AMD Radeon HD 6770M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
85W | 114W | 290 BTU/h | 389 BTU/h |
iMac (27-inch, Mid 2011) | |||
|---|---|---|---|
27-inch display, 2.7GHz Intel Core i5, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, AMD Radeon HD 6770M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
135W | 170W | 461 BTU/h | 580 BTU/h |
iMac (27-inch, Mid 2011) | |||
|---|---|---|---|
27-inch display, 3.1GHz Intel Core i5, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, AMD Radeon HD 6970M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
139W | 195W | 474 BTU/h | 665 BTU/h |
iMac (27-inch, Mid 2011) | |||
|---|---|---|---|
27-inch display, 3.4GHz Intel Core i7, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, AMD Radeon HD 6970M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
142W | 200W | 485 BTU/h | 682 BTU/h |
iMac (Mid 2010) | |||
|---|---|---|---|
21.5-inch display, 3.6GHz Intel Core i5, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, ATI Radeon 4670 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
94W | 241W | 321 BTU/h | 822 BTU/h |
iMac (27-inch, Mid 2010) | |||
|---|---|---|---|
27-inch display, 3.2GHz Intel Core i3, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, ATI Radeon 5670 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
* | 365W | * | 1,245 BTU/h |
iMac (27-inch, Mid 2010) | |||
|---|---|---|---|
27-inch display, 3.6GHz Intel Core i5, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, ATI Radeon 5670 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
145W | 365W | 495 BTU/h | 1,245 BTU/h |
iMac (21.5-inch, Late 2009) | |||
|---|---|---|---|
21.5-inch display, 3.33GHz Intel Core 2 Duo, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 500GB Serial ATA hard drive, NVIDIA GeForce 9400M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
104W | 241W | 355 BTU/h | 822 BTU/h |
iMac (21.5-inch, Late 2009) | |||
|---|---|---|---|
21.5-inch display, 3.2GHz Intel Core i3, 4GB 1333MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, NVIDIA GeForce 9400M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
104W | 241W | 355 BTU/h | 822 BTU/h |
iMac (27-inch, Late 2009) | |||
|---|---|---|---|
27-inch display, 3.06GHz Intel Core 2 Duo, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, ATI Radeon 4670 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
* | 365W | * | 1,245 BTU/h |
Power Consumption Of Mac Apps
iMac (27-inch, Late 2009) | |||
|---|---|---|---|
27-inch display, 3.33GHz Intel Core 2 Duo, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, ATI Radeon 4670 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
* | 365W | * | 1,245 BTU/h |
iMac (27-inch, Late 2009) | |||
|---|---|---|---|
27-inch display, 2.66GHz Quad-core Intel i5, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, ATI Radeon 4850 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
145W | 365W | * | 1,245 BTU/h |
iMac (20-inch, Early 2009) | |||
|---|---|---|---|
20-inch display, 2.66GHz Intel Core 2 Duo, 2GB 1066MHz DDR3 SDRAM - 2x1GB, 320GB Serial ATA hard drive, NVIDIA GeForce 9400M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
60.7W | 108.9W | 206.4 BTU/h | 371.6 BTU/h |
iMac (24-inch, Early 2009) | |||
|---|---|---|---|
24-inch display, 2.66GHz Intel Core 2 Duo, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 640GB Serial ATA hard drive, NVIDIA GeForce 9400M graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
104.4W | 151.5W | 355 BTU/h | 515.2 BTU/h |
iMac (24-inch, Early 2009) | |||
|---|---|---|---|
24-inch display, 2.93GHz Intel Core 2 Duo, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 640GB Serial ATA hard drive, NVIDIA GeForce GT 120 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
116.4W | 192.2W | 395.8 BTU/h | 653.5 BTU/h |
iMac (24-inch, Early 2009) | |||
|---|---|---|---|
24-inch display, 3.06GHz Intel Core 2 Duo, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, NVIDIA GeForce GT 130 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
113.9W | 208.9W | 387.3 BTU/h | 710.3 BTU/h |
iMac (24-inch, Early 2009) | |||
|---|---|---|---|
24-inch display, 3.06GHz Intel Core 2 Duo, 4GB 1066MHz DDR3 SDRAM - 2x2GB, 1TB Serial ATA hard drive, ATI Radeon HD 4850 graphics | |||
Power Consumption | Thermal Output | ||
Idle | CPU Max | Idle | CPU Max |
125.5W | 215.7W | 426.7 BTU/h | 733.4 BTU/h |
* Information not available.
Notes
- Power consumption data (watts) is measured from the wall power source and includes all power supply and system losses. Additional correction isn't needed.
- CPU Max is defined as running a compute-intensive test application that maximizes processor usage and therefore power consumption.
- These numbers reflect a 23°C (73.4°F) ambient running environment. Increased ambient temperatures require faster fan speeds which increases power consumption. At 35°C (95°F), 50W should be added to reflect increased power consumption.