Alarmingly High CPU Temperature on 2020 27" iMac

[quagmire]

I know the i9-10900K has been shown to draw over 300W with all cores at ~5GHz and needs a very capable liquid cooling system to operate at that speed. As I recall, Anandtech also needed to use very capable liquid cooling on the 9900K because it had to be well into the triple-digits on wattage.

I dug up the article. The 9900K unleashed hit 165W in their testing.

Here is the chart with the CPU frequency differences.

Full article here:

The Intel Core i9-9900K at 95W: Fixing The Power for SFF

www.anandtech.com

 

[bousozoku]

That's wild.

I regularly see 100 degrees C on my mid-2012 MacBook Pro with quad-core processor while working on video, but I've seen 104 recently. I can't imagine 127 degrees C being possible without the processor shutting down.

 

[getrealbro]

100º C within 90 seconds of starting a transcode in HandBrake.

View attachment 945627

Thanks for the info. That’s what I would expect with HandBrake transcoding.


FWIW My 3.2GHz 6 core i7 Mini hits nearly 100c quicker than that when transcoding via HandBrake.

BTW I run Intel Power Gadget with a screen update of 750ms and sampling of 500ms to get the Power Gadget graphs to roughly align with the Activity monitor CPU History graph at the same width. The windows overlap so not all cores are visible.

Now my only question is how loud is the fan on a 2020 i7 iMac? But that perception depends a lot of the physical setting and each individual’s sensitivity to specific sounds.

Luckily we don’t have to upgrade my wife’s iMac yet. And a friend is planning to get a 2020 i7 iMac “real soon”, which i have volunteered to configure. So I’ll get a chance to see how loud we think it is under load before we have to decide to get a 2020 i7 iMac or 2018 i7 Mini

GetRealBro

 

[1229175]

Thanks for the info. That’s what I would expect with HandBrake transcoding.

View attachment 945650
FWIW My 3.2GHz 6 core i7 Mini hits nearly 100c quicker than that when transcoding via HandBrake.

BTW I run Intel Power Gadget with a screen update of 750ms and sampling of 500ms to get the Power Gadget graphs to roughly align with the Activity monitor CPU History graph at the same width. The windows overlap so not all cores are visible.

Now my only question is how loud is the fan on a 2020 i7 iMac? But that perception depends a lot of the physical setting and each individual’s sensitivity to specific sounds.

Luckily we don’t have to upgrade my wife’s iMac yet. And a friend is planning to get a 2020 i7 iMac “real soon”, which i have volunteered to configure. So I’ll get a chance to see how loud we think it is under load before we have to decide to get a 2020 i7 iMac or 2018 i7 Mini

GetRealBro

Are you able to run your 40GB/day of transcodes from .ts to .mp4 using a GPU-accelerated encoder? Using the VideoToolbox H.264 and HEVC encoder in HandBrake would significantly speed up your conversions. The T2-powered encoder in Apple Compressor would, as well.

 

[wilberforce]

10-core i9 27-inch iMac TESTED! Is There A Thermal Problem? Benchmarks & Analysis!

Sorry if already posted

 

[rluciano]

Is this putting anyone else off ordering a 2020 iMac?

It just feels a bit dirty of Apple to release these chipsets in the current design, with only one, small fan.

I returned my top spec 27" iMac. I was seeing 65ºC CPU temps loafing around and 96-102º under load (Handbrake). It was hot and loud. And if I ran Cinebench or Geekbench after CPU was hot, benchmarks dropped by over 30% versus a just booted computer.

 

[1229175]

10-core i9 27-inch iMac TESTED! Is There A Thermal Problem? Benchmarks & Analysis!

Sorry if already posted

It seemed to me like the reviewer defined "thermal issues" as whether the processor dropped below the advertised clock speed. He never addressed temperature.

 

[jobinhosyntax]

It seemed to me like the reviewer defined "thermal issues" as whether the processor dropped below the advertised clock speed. He never addressed temperature.

For many users--myself included--this is the most important factor. While not ideal, its great to see a sustained performance on the i9. I wouldn't want be flying without apple care mind...

 

[wilberforce]

This is running Cinebench on my 2014 iMac i7. Seems like this 2014 iMac has more "thermal issues," with frequency throttled to much less than base 4 GHz, temperature near 100C, and fan at full speed:

 

[1229175]

From what I've gathered with all the excellent feedback here, it just seems that Apple has always kept the CPU in iMac uncomfortably close to (or even at and sometimes exceeding) 100º C. It looks like the problem has become progressively worse with Intel's latest CPUs, but this has been an issue for the past decade.

Is this correct?

I'm asking because my last iMac was a 2007 model I had for a few years and then switched to building Linux- and Windows-powered workstations with custom cooling. I've always kept my CPUs under 85º at max load, so seeing 100º C in these iMacs is just not what I'm used to.

 

[rluciano]

From what I've gathered with all the excellent feedback here, it just seems that Apple has always kept the CPU in iMac uncomfortably close to (or even at and sometimes exceeding) 100º C. It looks like the problem has become progressively worse with Intel's latest CPUs, but this has been an issue for the past decade.

Is this correct?

I'm asking because my last iMac was a 2007 model I had for a few years and then switched to building Linux- and Windows-powered workstations with custom cooling. I've always kept my CPUs under 85º at max load, so seeing 100º C in these iMacs is just not what I'm used to.

100ºC may well be okay for the CPU itself, but I worry about what that heat will do to the rest of the computer over time. I usually keep my computers 5-7 years and I use them for more than just web-browsing. 😉

 

[rkuo]

You know what, that's it. I'm out. I've had a whole post already typed explaining how a CPU operated at 99.7 °C might only last 161 instead of 161 years, and how statistics contradict CPU death by temperature, yaddah yaddah yaddah. But I have now come to accept that it is utterly pointless do waste any more of my time in here. This thread has reached the point of breathtakingly stupid conspiracy theories, and quite frankly my time is too valuable to argue with conspiracy theorists on the internet.


View attachment 945579

Peace. I'm out.

Unfortunately, you're not correct. I have run Mac's in datacenters and running them at 100C constantly causes a much higher failure rate over time. Once, we accidentally configured some mini's behind some other mini's. The "throttling" did nothing to save them ... they started failing like crazy.

It might not be as bad if you only burst to 100C occasionally, but I try hard not to let it happen, and that's based on facts.

 

[getrealbro]

Are you able to run your 40GB/day of transcodes from .ts to .mp4 using a GPU-accelerated encoder? Using the VideoToolbox H.264 and HEVC encoder in HandBrake would significantly speed up your conversions. The T2-powered encoder in Apple Compressor would, as well.

Thanks for the reply. I really don’t know if I could use the T2, etc. to improve the speed of the transcoding. I only recently began capturing RTSP feeds from a couple of wildlife cameras. And muddled my way through various apps to get the .ts video converted to a more usable .mp4 format that Quick Time Player likes. I’ll see if I can do better.

BTW I ran the same Cinebench test on our 2013 iMac and 2014 Mini. They were painfully slow, but also much slower to get to a high temp and crank up the fan

Based on my testing and reading posts in this and other threads, my take is that the recent Intel 6 & 8 core i7 are high wattage chips that run pretty hot even when doing very little but give some nice performance boosts when pushed. Unfortunately Apple’s cooling system for these chips (in the 2018 Mini and 2020 iMac) appears to be designed to use these Macs/chips as sprinters, not work horses.

I can live with that as long as the 2020 8 core i7 iMac’s fan noise is as quiet as my 2018 6 core i7 Mini’s.

GetRealBro

 

[1229175]

Thanks for the reply. I really don’t know if I could use the T2, etc. to improve the speed of the transcoding. I only recently began capturing RTSP feeds from a couple of wildlife cameras. And muddled my way through various apps to get the .ts video converted to a more usable .mp4 format that Quick Time Player likes. I’ll see if I can do better.

If the codec in the .ts files is something like H.264, you don't even need to transcode in HandBrake. Open the files in VLC and resave in an MP4 container (File > Convert / Stream... > Custom profile). It saves a new file in an MP4 container using the existing video stream, so there's no re-encoding involved.

 

[1229175]

100ºC may well be okay for the CPU itself, but I worry about what that heat will do to the rest of the computer over time. I usually keep my computers 5-7 years and I use them for more than just web-browsing. 😉

I highly doubt this 2020 27" iMac will last 5–7 years, unfortunately. Not with its questionable thermal management system for this over-cored and over-clocked Intel CPU.

 

[KrazyKanuck]

I highly doubt this 2020 27" iMac will last 5–7 years, unfortunately. Not with its questionable thermal management system for this over-cored and over-clocked Intel CPU.

Yet, I find there's something oddly charming and characterful about an overpowered and undercooled machine that will tear itself to pieces if you ask it to.

 

[JCon63]

Yet, I find there's something oddly charming and characterful about an overpowered and undercooled machine that will tear itself to pieces if you ask it to.

I find it funny that some here want this machine to be bad...
It's not.

 

[KrazyKanuck]

I find it funny that some here want this machine to be bad...
It's not.

How could anybody stare into those big black bezels and not have their heart melt?

 

[getrealbro]

From what I've gathered with all the excellent feedback here, it just seems that Apple has always kept the CPU in iMac uncomfortably close to (or even at and sometimes exceeding) 100º C. It looks like the problem has become progressively worse with Intel's latest CPUs, but this has been an issue for the past decade.

Is this correct?
.....

I think flirting with 100C is more recent than that. My 2013 dual core i5 iMac and my 2014 dual core i5 Mini both run very cool even when pushed a bit. But they are pitifully slow compared to my 2018 6 core i7 Mini that is easily pushed to just under 100c.


Cinebench on the 2013 iMac


Cinebench on the 2014 Mini

Note: Details of the processors are in the Cinebench window.

GetRealBro

Edit: Added the screen dump of my 2013 iMac AFTER to got hot and cranked up the fan, for those who believe this doesn’t happen on older iMacs. With weaker CPUs it just takes a little longer

 

[filmgirl]

From what I've gathered with all the excellent feedback here, it just seems that Apple has always kept the CPU in iMac uncomfortably close to (or even at and sometimes exceeding) 100º C. It looks like the problem has become progressively worse with Intel's latest CPUs, but this has been an issue for the past decade.

I fundamentally disagree with the “progressively worse” part. Every iMac I’ve used since 2009 has had some degree of running hot under sustained load. The question is is it too hot. Here, my own experiences tell me it isn’t. Would a second fan be nice, hell yes, and I think with the 2020 model especially, it is sort of dumb to have this completely manufactured and purposeful distinction between the iMac 5K and the iMac Pro, especially since it seems clear the iMac Pro will never get another update and it is a worse machine in nearly every other respect (cooling and two TB3 buses are the only area I find it better and I am personally unwilling to pay a premium for OLD hardware and RAM I can’t upgrade without a trip to the Apple Store), but that's secondary to whether the heat has gotten worse or if the heat is even a problem.

Again, I’m not defending the lack of a second fan — but I trust Apple and Intel to not sell something that is over tolerance. Also consider that Apple's deal with Intel means Apple gets the highest quality silicon.

Unfortunately, you're not correct. I have run Mac's in datacenters and running them at 100C constantly causes a much higher failure rate over time. Once, we accidentally configured some mini's behind some other mini's. The "throttling" did nothing to save them ... they started failing like crazy.

It might not be as bad if you only burst to 100C occasionally, but I try hard not to let it happen, and that's based on facts.

Respectfully, comparing an iMac to a Mac mini in a data center without proper ventilation is a total strawman. If your iMac's vents are blocked, that’s going to be a problem too.

 

[petsk]

it seems clear the iMac Pro will never get another update

iMac Pro is probably getting an update in Q4

 

[Nicole1980]

I fundamentally disagree with the “progressively worse” part. Every iMac I’ve used since 2009 has had some degree of running hot under sustained load.

I have to 'fundamentally disagree' with that. I've got a 2019 6-core i5 imac with the Vega 48 and do 4k video editing and after effects work on it. It pretty much NEVER gets above 60c. EVEN with renders that last 1 or more HOURS!

Maybe I just got lucky with one that has the exact right amount of thermal paste or whatever, but in my experience, at least with the 6-core, if your iMac is often having the fans spinning up or getting anywhere near 100c then there's probably something wrong with the machine.

 

[jobinhosyntax]

iMac Pro is probably getting an update in Q4

Is it not more likely iMac Pro will be mothballed into Apple Silicon iMacs next year?

 

[1229175]

Is it not more likely iMac Pro will be mothballed into Apple Silicon iMacs next year?

iMac Pro will likely be upgraded with Apple Silicon. That would allow Apple to continue selling it at a 2–3x premium because of the "Pro" label.

 

[1229175]

I fundamentally disagree with the “progressively worse” part. Every iMac I’ve used since 2009 has had some degree of running hot under sustained load. The question is is it too hot. Here, my own experiences tell me it isn’t. Would a second fan be nice, hell yes, and I think with the 2020 model especially, it is sort of dumb to have this completely manufactured and purposeful distinction between the iMac 5K and the iMac Pro, especially since it seems clear the iMac Pro will never get another update and it is a worse machine in nearly every other respect (cooling and two TB3 buses are the only area I find it better and I am personally unwilling to pay a premium for OLD hardware and RAM I can’t upgrade without a trip to the Apple Store), but that's secondary to whether the heat has gotten worse or if the heat is even a problem.

If only iMac had iMac Pro's cooling system. This would be a complete non-issue then.

Again, I’m not defending the lack of a second fan — but I trust Apple and Intel to not sell something that is over tolerance. Also consider that Apple's deal with Intel means Apple gets the highest quality silicon.

I don't believe Apple trusts Intel anymore, hence their migration towards Apple Silicon. It seems that Apple is just as frustrated with Intel's lack of progress and repetitive 14+++++ nm architecture as we all are.