Constant fan noise on 2017 iMac even at rest

What's causing the fan activity depends on which fan it is. But if the fan is that noisy, I'd suggest you use your free Apple Support to get in touch with them and have it checked.

Have you tried n SMC reset?

Reset the System Management Controller (SMC) on your Mac - Apple Support

I had the 4.2Ghz, 16GB RAM, 3TB Fusion. The fan was super loud and today was my 14th day. I returned it. Using my 2011 iMAC and its super quiet. Hoping to get another iMAC in the future or the Mac Pro system.

I have the same problem with my new Imac: 14 days to give my money back....I return it....My mid 2011 Imac 27 inch still very quiet compare to the Fan noisy of new Imac 2017

27-inch iMac with Retina 5K display

Configuration

• 4.2GHz quad-core 7th-generation Intel Core i7 processor, Turbo Boost up to 4.5GHz

• 8GB 2400MHz DDR4

• 2TB Fusion Drive

• Radeon Pro 580 with 8GB video memory

Holger,

A SMC reset is the normal thing to do if you have fan noise. Sometimes it takes 2-3 times for the reset to work though, so don't be discouraged if it doesn't work the first or second time. Below is a link that shows how to do it and also one for doing a PRAM reset. These are both very basic and in no way affect your data on the computer. If you want to Google them to learn what they are that's fine.

iMac SMC and PRAM reset

The past four generations of 21.5-inch and 27-inch iMac (including yours) have only had one internal fan (blower). Earlier iMac models contained 3 fans (blowers). In all models the fan(s) turn on almost immediately after the power button is pressed, and the fan (blower) speed adjusts constantly depending on the internal sensor values.

My 2017 27-inch iMac is nearly silent unless I put my ear up to the display. It sounds like your iMac is much louder than normal, or you are more sensitive to the noise it makes. How far away are you sitting when you hear the noise? Can you hear it from across the room too?

I suggest running the Apple Diags that are already installed on your iMac to see if the diags detect any sensor or fan speed errors. If an error is generated be sure to record the details and take your iMac to a service location. You can also take it in if the idle fan (blower) noise is abnormally loud.

How to use Apple Diagnostics on your Mac - Apple Support

One additional step to take is to run the Activity Monitor application located in the Applications/Utilities folder. Click on the CPU option at the top and monitor the CPU usage. For new systems you may observe processes related to things like Spotlight or the Photos app consuming processor time and potentially causing the fan to run a little bit faster temporarily. Make a note if there are any processes consistently using a large % of the CPU time and report the results.

Wienandy wrote:

I also have a similar problem with a 2017 iMac. Diagnostics show no problems both at home and at the Apple support service provider. Although Apple agreed to a replacement a shipping problem by Apple means I am well past my 14 days to return the machine. Apple Support are now very quiet and I still have a noisy iMac. Any ideas anyone?

Reset the SMC 2-3 times back to back and re-test. Intel iMac SMC and VRAM resets

and make these tests too...and still noisy !!!

Mac SMC and PRAM reset

105680 Views | Last Modified: May 16, 2014

SMC RESET

• Shut down the computer.
• Unplug the computer's power cord from both the wall and computer.
• Wait 15 seconds.
• Attach the computers power cable.
• Wait another 5 seconds and press the power button to turn on the computer.

PRAM RESET

• Shut down the computer.
• Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4.
• Turn on the computer.
• Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
• Hold the keys down until the computer restarts and you hear the startup sound for the second time.
• Release the keys.

I am having the same issue with my new iMac. Similar specifications to JackLePage:

• Retina 5K, 27-inch, 2017
• 4.2 GHz Intel Core i7
• 8 GB 2400 MHz DDR4
• Radeon Pro 580 8192 MB

There's a constant hum of fan noise compared to the whisper quiet iMac 2015 3.1 GHz Intel Core i5 / 8GB 1867 MHz DDR3 / Intel Iris Pro Graphics 6200 1536 MB. With the exception of Safari and email, I really haven't started using it yet and I am fearful it's going to get noisier as I start using the Applications.

I too am considering returning it within the 14 days of delivery. What is the cause for the fan noise? Is it the Intel Core i7 and/or video card? Would upgrading the RAM help in anyway?

I just got mine yesterday. I was reading a lot about fan noise and was a bit worried. But at idle and in most applications so far, it is just very quiet. I noticed when I tried to watch 8k YouTube video, then the fan will go on. As soon as I picked 4k or 5k option, the fan quieted down again. My config:

Configuration

• 4.2GHZ QC I7, TB UP TO 4.5GHZ
• 8GB 2400MHZ DDR4 - 2X4GB
• FLASH STORAGE
• AMD RADEON PRO 580 W/8GB VRAM

No, I'm saying you have several fans in an iMac. Whichever fan it is, it may be a hardware defect. You don't have to google the SMC reset, just use the link I gave you.

Besides your free AppleCare, you also have 14 days to return the Mac for a full refund.

It's not a common problem, remember what you read on the Internet isn't always fact. Also remember people come to help forums to find a solution to a problem or to just complain. They don't represent the millions of silent users that have never post.

I had that issue too. Had sent my 2011 iMac off for repair, when it came back the fan was so loud. I did a SMC reset and all is fine since. I think something got knocked while the Mac was in transit and just needed a reset.

I also have a similar problem with a 2017 iMac. Diagnostics show no problems both at home and at the Apple support service provider. Although Apple agreed to a replacement a shipping problem by Apple means I am well past my 14 days to return the machine. Apple Support are now very quiet and I still have a noisy iMac. Any ideas anyone?