I've had overheating issues with my last Mac and am now trying to avoid this with an Imac.

I saw this which reaffirmed my fears:

Does anyone know of an app or the best settings to put into an app to keep things running optimal to prevent throttling or damage from heat. MacFanControl didn't seem to do anything, in fact it dissabled my system fans..

 

you wont need any app, just phisically clean your fans

 

The problems with macs is that cooling is of lower priority to apple than slick design. So that's why they changed some parameters under the hood of macos to make the fans ramp up later than they should to make them more quiet. You immediately notice that if you install windows via bootcamp. Fans ramp up much quicker than in macOS. Although windows usually need less resources than macos if I'm not mistaken. But it's more of an issue on MacBook Pros than on iMacs.

Anyway: you could get SMCFan Control App to override the default settings. But make sure the fans, the air intakes and exhausts are dust free for optimum air flow. Because ramping up the fans speed doesn't help when there's no free passage for the air to pass through the system.

 

Thanks for the tips! I'll check out SMCFan App. I guess I need to figure out how to clean the tiny slits in the bottom of the imac. My concern is because the 2019 imac is very thin and compact so it would seem things would heat up with all the components crammed on top of each other. I'm really pushing the cpu with my sessions too so things stay hot for a while...

 

I'd look up your iMac Model and then check out the teardown of it on iFixit to see how complicated it is to remove the backplate and clean the fans, etc. But since it's only about a year old it probably won't have collected much dust unless you have carpet on the floor or any fury pets. So this overheating issue will probably remain. There are tools to monitor the temperatures. I think if the CPU temps exceed 90 something degrees C the system starts to thermal throttle. I use HWmonitor on my Hackintosh. Should work on a regular mac too, just DONT install the kexts it comes with.

 

"Adequate" cooling depends on which iMac 2019 you have. Is it the i3, the i5 the i7 ? Which one ? For all of these the provided cooling solution is adequate except perhaps the top i7 model, but then again theoretically it should be within the safe operational margin. If i remember correctly, the cooling solution is identical to all these models but each of them generates different amount of heat according to which cpu it uses.
Where it's definitely not enough is on the iMac Pro Models.
For example, even the iMac Pro base model (8 core Xeon @ 3.2ghz) can reach easily 95 degrees Celcius under consistent full load, which will cause it to thermal throttle, thus lower the cpu clock in order to compensate for the heat produced, until it gets back to safe operational temperatures. Still we 're talking bout an 8c/16t cpu with a relatively high turbo boost here (for a Xeon). "Plain" iMacs should be able to handle cpu load much more easily.
Cheers

 

You can also check Fan Speed via Terminal
sudo powermetrics | grep Fan

 

Its the i9 8core (non pro). I'll look into adjusting clock speeds also but it seems a shame to have to do.. I'm also going to pay more attention to temperatures but heat is what ultimately KO'd my last mac....

Thanks!

 

Jesus and Mary Chain mate . That is quite hardcore for a slim iMac, you 've got the 9900k version. Great display, cool looks. Quite expensive of course. I haven't had the chance to put my hands on one such as yours in the test bench, but everywhere i look in the web, supposedly Apple managed to fix the 2017-2018 fiasco of constant cpu throttling. It looks like they made the whole cpu boost scheme much more efficient now. So what this means in plain words? Means the cpu may not reach 5 ghz when turboing but it will NEVER drop below the base clock.
For those reading but don't understand what turbo boost is and how it works, first of all it is not overclock. It is an automatic boost which is done dynamically by the system depending on the workload executed at any given moment. So the i9 9900k has a base clock of 3.6 ghz but can turboboost, that is reach, to 5 ghz. But this is not an all core boost. This is only stands for the first two cores, when core 3 and 4 are active too, under load the cpu can boost up to 4.8ghz. And finally from 5 cores up to a full 8 cores active under full load, the cpu may reach 4.7 max. This is all on paper of course, your experience may vary no matter the OS platform, but not very far from the advertised speeds.
Now on your iMac it is reported that Apple did a much better job than on previous models, so in order to keep thermals under control you may not see the advertise boosts as on a normal desktop with a hefty cooling solution but as mentioned you will never have to worry bout your cpu operating below its base clock. To be honest, i find this fantastic for such a slim,sleek machine. So most likely you have a slim gem in your hands and probably needn't worry.
Cheers
Ps: Some video about this :

 

Last edited: Feb 2, 2020

Sounds like good news! The 5k screen is a bit overkill. I would omit that feature if possible but otherwise as long as the slim-ness doesn't affect the performance issue other then what you mentioned regarding CPU I'm happy. I've got Apple care so maybe I'll see if I can take it in for annual cleaning during that period. I'm hoping Apple is turning a corner because this imac is ram upgradable and drive swappable.

 

Hey @KungPaoFist ! How does the iMac is working for you? Is it as noisy as people say?

Like this guy here, at #169 comment:
https://forums.macrumors.com/thread...nt.2218800/page-7?post=28232890#post-28232890

 

I wouldn't say noise is the biggest issue but it's actually a lot quieter then the noisy air-conditioner sitting next to it.