2014 iMac lag with fan noise!

[andrew_salfinger]

Hello, I've been having a issue with my iMac (Retina 5K, 27-inch, Late 2014) where the Mac is either sitting ideal or just watching a video where the fans will crank up really loud and the Mac is self will start to lag, where the video will stutter, the computer it self will lag (so moving the mouse or window will lag)

I tried take the iMac to Apple but they said it was to old for them to help / even look at.

I used iSat to get get some info if that helps:

Would anyone know why the iMac is acting this way and or ways to maybe fix it?

I was originally thinking it was something to do with the CPU / thermal paste might needed to be re-applied?

Thank you for your time,
Andrew.

 

[Nguyen Duc Hieu]

It seems to me that your CPU temp is a little high.
Safari and software updater are occupying CPU.

Can you try running the OS from an external device (SSD on USB 3.0 box, with freshly installed OS) to eliminate factors from OS?

 

[wilberforce]

Well that is pretty weird, as the max fan speed for the late 2014 5k iMac is supposed to be 2700 rpm not 3600 rpm (I know this for sure, I used to own one). Does MacsFanControl show the same fan speed?

Also, the fan speed usually only hits 2700 rpm when CPU is close to 99 degrees. None of those temperatures look very high.
Something wrong with the fan speed control?

Download and try MacsFanControl to see if you can manually control the fan speed (i.e., to see if the fan speed is controllable, which it should be).

Assume you have already reset SMC?

Reset the SMC of your Mac - Apple Support

The SMC is responsible for managing power on your Mac. Resetting it can resolve certain uncommon issues related to power or thermal management.

support.apple.com

Also try Intel Power Gadget to see if your CPU is being throttled and its utilization

 

[andrew_salfinger]

Well that is pretty weird, as the max fan speed for the late 2014 5k iMac is supposed to be 2700 rpm not 3600 rpm (I know this for sure, I used to own one). Does MacsFanControl show the same fan speed?

Also, the fan speed usually only hits 2700 rpm when CPU is close to 99 degrees. None of those temperatures look very high.
Something wrong with the fan speed control?

Download and try MacsFanControl to see if you can manually control the fan speed (i.e., to see if the fan speed is controllable, which it should be).

Assume you have already reset SMC?

Reset the SMC of your Mac - Apple Support

The SMC is responsible for managing power on your Mac. Resetting it can resolve certain uncommon issues related to power or thermal management.

support.apple.com

Also try Intel Power Gadget to see if your CPU is being throttled and its utilization

I've tried a SMC and I also just tried MacsFanControl and it seems I'm able to control the fan. I have not yet tired the Intel Power Gadget.

 

[andrew_salfinger]

It seems to me that your CPU temp is a little high.
Safari and software updater are occupying CPU.

Can you try running the OS from an external device (SSD on USB 3.0 box, with freshly installed OS) to eliminate factors from OS?

I don't have a external SSD to try the with. However I have done a fresh install of the Mac before and it seemed to not fix the issue.

 

[andrew_salfinger]

Also try Intel Power Gadget to see if your CPU is being throttled and its utilization

Just installed Intel Power Gadget and this is what information it displayed.

 

[wilberforce]

Just installed Intel Power Gadget and this is what information it displayed.

Ok, I don't know enough about this to help you, but a number of things look odd to me. The CPU frequency is dropping to a very low value, and despite the CPU temperature dropping the fan is still running at 3600 rpm, when that iMac fan max speed should be 2700 rpm (at least, mine was, and so is my 2020 5k iMac).

 

[The_Croupier]

Could be a temp sensor failure? Have you run AHT?

 

[avz]

Keep in mind that Apple used the same CPU in your 2014 iMac, as they used with the "2K" 2013 iMac. Your 5K display makes it work harder plus recent macOS may be more taxing on your old CPU as well.

 

[andrew_salfinger]

Could be a temp sensor failure? Have you run AHT?

Yes I have with 0 issues reported.