SMC Fan Control not working under Sierra

As per this article : About fans and fan noise in your Mac - Apple Support

About fan noise

If your computer's processor is working on intensive tasks—such as compressing HD video, playing a graphics-heavy game, or indexing the hard drive with Spotlight after you migrate data—the fans run faster to provide additional airflow. You might hear fan noise when this happens, especially if you're in a quiet environment. This rushing-air sound is a normal part of the cooling process.

Ambient temperature, the temperature outside the computer, also plays a role in the fans' responsiveness. If the ambient temperature is high, the fans turn on sooner and run faster.

Make sure the vents on your Mac aren't blocked

Mac computers have vents that let its fans bring in cool air and expel hot air. Make sure that the vents aren't blocked to allow your computer to perform at its best.

• On Mac notebooks, the vents are along the side and in the back.
• iMac computers have vents along the bottom edge and on the back.
• Mac mini models bring in cool air from beneath the computer and vent hot air from the back.
• Mac Pro (Late 2013) brings in cool air through vents at the bottom of the computer and sends out hot air from the top.

The surface your Mac rests on can block its vents, affecting fan behavior. If you use your computer on a soft surface like a couch, pillow, bed, or your lap, its fans might run more. Using your Mac on a hard, flat surface like a table or desk is best for temperature control.

Make sure you follow these above steps and quit running applications : See how apps affect Mac performance, battery runtime, temperature, and fan activity - Apple Support

Click on the sub articles in see how apps affect Mac performance , battery runtime , temperature and fan activity .

applemachanic wrote:

slightly excessive response - SMC fan control has been widely used since 2007 with only great results and has extended the life of many machines !

That is completely untrue, harmful advice.

Whether or not that advice is harmful depends greatly on the circumstance. Not messing with your fan speeds is ALMOST always good advice. I am sure any iMac user who decided to upgrade their HDD for an SSD in turn making their fan spin faster than a Ducati nonstop will beg to differ though.

Using a fan control utility should be the exception and not the rule. But there are situations were it is needed.

In my case, the Late 2009 27" iMac uses a disk with custom Apple firmware, that provided the disk temperature. The disk itself was prone to higher failure rates than other disks. You either got the Apple branded replacement, and suffered a failure again in a few years, or you used a 3rd party.

Using a 3rd party disk causes that model iMac to send the fans into Overdrive! The solution was a utility that uses the disk's S.M.A.R.T. data to monitor the temperature, and adjust the fans accordingly. There are several, but I was using SSD Fan Control.

I eventually got a special SATA cable from OWC MacSales.com that included a chip that emulated the custom Apple firmware which reported disk temps.

That 8 year old iMac is still my work iMac which gets used every week day, runs the groups web server, does backups for some critical group services, etc... If I had not been able to run a fan control app, I would have had to pay for an expensive unreliable disk every 2 years for the pat 8 years. Now I have a higher capacity more reliable disk, and a very useful iMac.

Exceptions to the general rules of thumb exist.

slightly excessive response - SMC fan control has been widely used since 2007 with only great results and has extended the life of many machines !

What operational problem do you need to address?

Using third party hacks to circumvent the Mac's cooling system are ill-advised. Unjustifiably higher fan speeds will draw in additional airborne contaminants needlessly, resulting in accelerated hardware failure. Reliance upon such products will only hide symptoms of an underlying problem that should be corrected, and can conceivably invalidate any applicable product warranty.

FWIW, I completely agree there is no good reason to be running SMC Fan Control. However, the developer's site clearly states version 2.6 is compatible with Sierra.