2017 iMac with i7 constantly hitting 100C?

thefriendshipmachine

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Apr 14, 2017
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My CPU is hitting 100C all the time (according to temperature guage). Is that normal/expected? It's a brand new 2017 iMac with i7. All I'm doing right now is installing xcode from the app store and installd is using a lot of the CPU and the machine is constantly hitting 100C CPU temps...

I thought the 2017 iMac would run *cooler* than my 2014 iMac but my 2014 i7 never hit 100C. So this seems like a problem to me?

edit: a screenshot of the "yes" command running in terminal, taken after 8 seconds https://s1-cdn.photoland.io/jO80s.png
 
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Trebuin

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My CPU is hitting 100C all the time (according to temperature guage). Is that normal/expected? It's a brand new 2017 iMac with i7. All I'm doing right now is installing xcode from the app store and installd is using a lot of the CPU and the machine is constantly hitting 100C CPU temps...

I thought the 2017 iMac would run *cooler* than my 2014 iMac but my 2014 i7 never hit 100C. So this seems like a problem to me?
It’s not healthy to run like that. I used turbo boost enabler to turn hyperthreading off & drop the temps when I really didn’t need the extra power.
 

propower

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Jul 23, 2010
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Yes - sadly that is normal for the 2017 i7. I returned mine...

In many normal use scenarios it will be fine but any task that hits the CPU significantly will ramp temps very quickly. Any render task I did when I had it would hit 100degC in less than a minute. Turning Turbo off made no difference.
 

mikeboss

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the 2017 iMac with an i7 CPU would drive me crazy. I had one on my desk for a weekend and the fan would spin up constantly because of the CPU getting hot very quickly. luckily, this was a customer's machine. I bought two i5 models for myself (entry level model). no matter what I do, the fan stays at 1200 RPM. single-thread performance is only 10% slower than the 2015 i7. of course this is a measureable difference, but throughout the day I couldn't tell if I'm on the 2015 i7 or the 2017 i5. fun fact: encoding with handbrake takes the same amount of time on the iMac 2017 with an i5 as it takes on my 6-core MacPro6,1.
 

Persian-apple

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Aug 16, 2012
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My CPU is hitting 100C all the time (according to temperature guage). Is that normal/expected? It's a brand new 2017 iMac with i7. All I'm doing right now is installing xcode from the app store and installd is using a lot of the CPU and the machine is constantly hitting 100C CPU temps...

I thought the 2017 iMac would run *cooler* than my 2014 iMac but my 2014 i7 never hit 100C. So this seems like a problem to me?
Listen man Im an owner of the Same machine 2017 i7 radeon pro 580 3tb fusion 16gb ram
And on the os x side While Using logic x with heavy plug ins the fans are barely turned on and it runs Super Cool
Under bootcamp and heavy games The fans Do become audible but i never Feel like Theyre too hot or something so id suggest you Order another one Dont listen to people sayin this is how the i7 is the i5 in the 2017imac is Kinda slower than my 2014 rmbp (i7) and It manages to cool it just fine why shouldnt an imac be able to cool an i7 while imac pro cools 18core processors?
 
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MH01

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Listen man Im an owner of the Same machine 2017 i7 radeon pro 580 3tb fusion 16gb ram
And on the os x side While Using logic x with heavy plug ins the fans are barely turned on and it runs Super Cool
Under bootcamp and heavy games The fans Do become audible but i never Feel like Theyre too hot or something so id suggest you Order another one Dont listen to people sayin this is how the i7 is the i5 in the 2017imac is Kinda slower than my 2014 rmbp (i7) and It manages to cool it just fine why shouldnt an imac be able to cool an i7 while imac pro cools 18core processors?
Fire up handbrake and report to us how long it takes for the fans to go to max.

Let's wait and see how the iMac pros cool.... are you assuming they will run quietly? Under full load ?
 

joema2

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My CPU is hitting 100C all the time...my 2014 i7 never hit 100C. So this seems like a problem to me?
If the same workload on your 2014 i7 iMac 27 did not cause these temps, that implies something's wrong with your 2017.

Are you measuring temp the same way with the same utility?
 

EugW

macrumors 604
Jun 18, 2017
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Unfortunately, this was the normal behaviour with my 2017 iMac i7-7700K. It was extremely easy to push it to 100C. This meant that the fan would come on loud after about half a minute of any CPU intensive activity, which bothered me more than the actual temperature.

So I returned the i7-7700K and got an i5-7600. Much happier.

My 2010 i7-870 definitely doesn’t behave like the 2017 i7-7700K. I cannot compare the 2014 since I never owned one.

the 2017 iMac with an i7 CPU would drive me crazy. I had one on my desk for a weekend and the fan would spin up constantly because of the CPU getting hot very quickly. luckily, this was a customer's machine. I bought two i5 models for myself (entry level model). no matter what I do, the fan stays at 1200 RPM. single-thread performance is only 10% slower than the 2015 i7. of course this is a measureable difference, but throughout the day I couldn't tell if I'm on the 2015 i7 or the 2017 i5. fun fact: encoding with handbrake takes the same amount of time on the iMac 2017 with an i5 as it takes on my 6-core MacPro6,1.
There are some reports here that suggest your entry level i5-7500 will stay cool enough basically forever, so it may never need the fan at a loud rpm, regardless of the workload intensity.

My i5-7600 will become audible after 10 minutes of Handbrake but without the fan at max.

My i7-7700K would hit max fan in ~30 seconds.
 
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mikeboss

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If the same workload on your 2014 i7 iMac 27 did not cause these temps, that implies something's wrong with your 2017.
nonsense! your statement would imply that every generation of i7s has the same thermal characteristics, which is clearly not the case.
 

T'hain Esh Kelch

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It’s not healthy to run like that. I used turbo boost enabler to turn hyperthreading off & drop the temps when I really didn’t need the extra power.
That is not correct! It is within thermal limits, and if it ever gets too hot, it will automatically shut down.
 

joema2

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nonsense! your statement would imply that every generation of i7s has the same thermal characteristics, which is clearly not the case.
You're right they *don't* have the same characteristics -- the 2014 i7 iMac was generally worse than the 2015 and 2017 i7. This is well known, has been discussed here many times and documented in various tests such as the below video.

Unfortunately when the OP asks about his 2017 i7 running much hotter than his 2014 i7, and people state "it's normal behavior", that is very misleading. There is no basis that the 2017 i7 iMac runs any hotter than the 2014 i7 iMac.

Apple's own power consumption figures show the 2017 i7 consumes significantly less power (hence produces less heat) at full load than the 2014 i7: https://support.apple.com/en-us/HT201918

Since the OP reported his 2017 i7 was dramatically worse than his similar 2014 i7, this might imply there's something wrong with his specific 2017 unit.

I own and use a 2013, 2015 and 2017 i7 iMac for professional video editing. I don't see any major difference in thermal behavior or fan noise, if anything the 2017 runs cooler and quieter.

This isn't to say the 2017 i7 is quiet under high load - it's not. There are definitely cases in a noise sensitive environment where a 2017 i5 might be the best choice. But that wasn't the OP's question. It was why is his 2017 i7 so much louder and hotter than his 2014 i7, apparently under similar loads.

However he did not categorically state his xcode workload was run identically on his 2014 i7, so it is conceivable he did not test them under equal scenarios.

Max Yuryev test:

 

mikeboss

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there are lots of reports all over the internet about the i7-7700K running too hot. it's not an issue with the iMac specifically, it's this CPU. it might work in a PC with a big cooler, but I wouldn't want this particular CPU in an iMac...
 
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joema2

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there are lots of reports all over the internet about the i7-7700K running too hot. it's not an issue with the iMac specifically, it's this CPU. it might work in a PC with a big cooler, but I wouldn't want this particular CPU in an iMac...
If you mean this ExtremeTech article (or similar) which reported problems *overclocking* the i7-7700K, that has nothing to do with the 2017 iMac: https://www.extremetech.com/computing/248908-intel-responds-i7-overheating-issue-cluelessly-suggests-stop-overclocking

The i7-7700K works fine in the 2017 iMac and it's no worse from a thermal or noise standpoint than a 2012, 2013 or 2015 i7 iMac. I own and use all those. It *is* roughly 2x faster (that's 200%) than the 2015 i7 on certain workloads like transcoding to/from H264 in FCPX, but it's no hotter while doing that than my 2013 or 2015 i7 iMac.

The OP reported his 2017 i7 was much hotter than his 2014 i7. There are only two possibilities: (1) His 2017 is defective, or (2) He's not running the same test or measuring it the same way as his 2014.

It is NOT "normal behavior" for the 2017 i7 iMac to run vastly hotter than the 2014 i7 iMac.
 

fokmik

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The 2017 imac has the same issue with cpu heat that ramps the fans that the 2014 had it with the m295x gpu that also hit 100c
 

maflynn

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My CPU is hitting 100C all the time (according to temperature guage). Is that normal/expected? It's a brand new 2017 iMac with i7. All I'm doing right now is installing xcode from the app store and installd is using a lot of the CPU and the machine is constantly hitting 100C CPU temps...

I thought the 2017 iMac would run *cooler* than my 2014 iMac but my 2014 i7 never hit 100C. So this seems like a problem to me?
Open up the activity monitor app (found in Applications->Utilities) and select all processes and see if there's any processes that are running that may be consuming your cpu
Capto_Capture 2017-12-26_10-13-38_AM.jpg
 

mikeboss

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I owned a 2015 i7 iMac for two years and I had the 2017 i7 on my desk for a whole weekend. the 2017's fan ramped up within minutes while I was working with/on it. this did never happen that quick with my 2015 model...

when I'm writing "all over the internet" I'm not referring to only one article. google it and you'll see.

transcoding with FCPX: bear in mind that newer machines have Intel Quick Sync Video. that's why a newer model will encode two times as fast. handbrake on the other hand uses the CPU per default. not quite the same.
 

thefriendshipmachine

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Apr 14, 2017
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Open up the activity monitor app (found in Applications->Utilities) and select all processes and see if there's any processes that are running that may be consuming your cpu
The two tasks that will case the CPU to spike up to 100C almost right away are:

1. when I install an app in App Store the installd process will ramp up to 130% CPU

2. when I boot windows inside VMWare Fusion

In my 2014 iMac these tasks would cause my CPU to heat up but never to 100C. I don't remember ever hitting CPU temps like that on the 2014 at all.

If you mean this ExtremeTech article (or similar) which reported problems *overclocking* the i7-7700K, that has nothing to do with the 2017 iMac: https://www.extremetech.com/computing/248908-intel-responds-i7-overheating-issue-cluelessly-suggests-stop-overclocking

The i7-7700K works fine in the 2017 iMac and it's no worse from a thermal or noise standpoint than a 2012, 2013 or 2015 i7 iMac. I own and use all those. It *is* roughly 2x faster (that's 200%) than the 2015 i7 on certain workloads like transcoding to/from H264 in FCPX, but it's no hotter while doing that than my 2013 or 2015 i7 iMac.

The OP reported his 2017 i7 was much hotter than his 2014 i7. There are only two possibilities: (1) His 2017 is defective, or (2) He's not running the same test or measuring it the same way as his 2014.

It is NOT "normal behavior" for the 2017 i7 iMac to run vastly hotter than the 2014 i7 iMac.
there are lots of reports all over the internet about the i7-7700K running too hot. it's not an issue with the iMac specifically, it's this CPU. it might work in a PC with a big cooler, but I wouldn't want this particular CPU in an iMac...
Is there any good benchmarks I can run that someone else with a 2017 i7 iMac could also run so we could compare notes to see if I have a dud?

Also... if this is "normal" is there any way to tell the fans to be more aggressive by themselves, or to even underclock the CPU?
 

maflynn

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The two tasks that will case the CPU to spike up to 100C almost right away are:

1. when I install an app in App Store the installd process will ramp up to 130% CPU

2. when I boot windows inside VMWare Fusion

In my 2014 iMac these tasks would cause my CPU to heat up but never to 100C. I don't remember ever hitting CPU temps like that on the 2014 at all.
That's not right.

I've use virtual machines (Fusion, VirtualBox) and the hottest I've seen my temps are mid 60s to 70s (Celsius). I'd call apple, I wonder if something is up with the thermal grease that was applied to the CPU, if its not applied correctly, then your iMac can overheat.
 
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mikeboss

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That's not right.

I've use virtual machines (Fusion, VirtualBox) and the hottest I've seen my temps are mid 60s to 70s (Celsius). I'd call apple, I wonder if something is up with the thermal grease that was applied to the CPU, if its not applied correctly, then your iMac can overheat.
as a staff member, you should not post misinformation. the i7-7700K max temp is 100 degrees celsius ->
https://ark.intel.com/products/97129/Intel-Core-i7-7700K-Processor-8M-Cache-up-to-4_50-GHz
[doublepost=1514304624][/doublepost]
Is there any good benchmarks I can run that someone else with a 2017 i7 iMac could also run so we could compare notes to see if I have a dud?

Also... if this is "normal" is there any way to tell the fans to be more aggressive by themselves, or to even underclock the CPU?
as others suggested already, you could try to disable turbo boost ->
https://github.com/rugarciap/Turbo-Boost-Switcher
https://www.rugarciap.com/2017/10/tbs-new-version-2-6-0/

transcode some video using handbrake, this will use the CPU to the max -> https://handbrake.fr
 

Trebuin

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That is not correct! It is within thermal limits, and if it ever gets too hot, it will automatically shut down.
You might be right...I'm more familiar with GPU limits using the manufacturing/design rule of 80C allowing for 20 years of life, reducing by half every 5C increased. That's an old number anyhow, given then changes when nVidia had their little disaster when they decided to go to disposable chips running at 100C. 100C is still not healthy, though. Intel in the past has started clocking down at 90C & minimized at 100C. My last deployment, my MacBook Pro would constantly hit 105C & conduct a hard shutdown somewhere around there.
[doublepost=1514305184][/doublepost]
The two tasks that will case the CPU to spike up to 100C almost right away are:

1. when I install an app in App Store the installd process will ramp up to 130% CPU

2. when I boot windows inside VMWare Fusion

In my 2014 iMac these tasks would cause my CPU to heat up but never to 100C. I don't remember ever hitting CPU temps like that on the 2014 at all.





Is there any good benchmarks I can run that someone else with a 2017 i7 iMac could also run so we could compare notes to see if I have a dud?

Also... if this is "normal" is there any way to tell the fans to be more aggressive by themselves, or to even underclock the CPU?
I agree with using handbrake (that's what I use all the time). There's also plenty of apps that can control the fans, I use the paid TG Pro, but there are just as good freeware out there. I actually adjust the settings to allow the fan to run faster than normal & ramp up to 100% between 70 & 80C to keep the temps cool.
 

thefriendshipmachine

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Original poster
Apr 14, 2017
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You might be right...I'm more familiar with GPU limits using the manufacturing/design rule of 80C allowing for 20 years of life, reducing by half every 5C increased. That's an old number anyhow, given then changes when nVidia had their little disaster when they decided to go to disposable chips running at 100C. 100C is still not healthy, though. Intel in the past has started clocking down at 90C & minimized at 100C. My last deployment, my MacBook Pro would constantly hit 105C & conduct a hard shutdown somewhere around there.
I am very concerned even if it is within its limits. My 2014's GPU burned my iMac's screen and caused Apple to replace the entire unit because that GPU ran hot in general and also the heatsink was not properly attached or something. The GPU reaching 100C caused physical damage to the machine and I would guess the CPU reaching 100C would also cause damage.

as a staff member, you should not post misinformation. the i7-7700K max temp is 100 degrees celsius ->
https://ark.intel.com/products/97129/Intel-Core-i7-7700K-Processor-8M-Cache-up-to-4_50-GHz
[doublepost=1514304624][/doublepost]

as others suggested already, you could try to disable turbo boost ->
https://github.com/rugarciap/Turbo-Boost-Switcher
https://www.rugarciap.com/2017/10/tbs-new-version-2-6-0/

transcode some video using handbrake, this will use the CPU to the max -> https://handbrake.fr
I will give disabling turbo a shot, thank you. Do you have a 2017 i7 btw?

That's not right.

I've use virtual machines (Fusion, VirtualBox) and the hottest I've seen my temps are mid 60s to 70s (Celsius). I'd call apple, I wonder if something is up with the thermal grease that was applied to the CPU, if its not applied correctly, then your iMac can overheat.
hey do you mind opening terminal and running the "yes" command and posting your temps where they peak before the fans kick in? Mine are:

https://s1-cdn.photoland.io/jO80s.png

and thank you.
[doublepost=1514305392][/doublepost]
You might be right...I'm more familiar with GPU limits using the manufacturing/design rule of 80C allowing for 20 years of life, reducing by half every 5C increased. That's an old number anyhow, given then changes when nVidia had their little disaster when they decided to go to disposable chips running at 100C. 100C is still not healthy, though. Intel in the past has started clocking down at 90C & minimized at 100C. My last deployment, my MacBook Pro would constantly hit 105C & conduct a hard shutdown somewhere around there.
[doublepost=1514305184][/doublepost]

I agree with using handbrake (that's what I use all the time). There's also plenty of apps that can control the fans, I use the paid TG Pro, but there are just as good freeware out there. I actually adjust the settings to allow the fan to run faster than normal & ramp up to 100% between 70 & 80C to keep the temps cool.
The problem is the CPU jumps from 60C to 100C in like 5 seconds so the fans are like "WHATS GOING ON?". Do you know of a tool where I can just say "as soon as the CPU crosses 68C BLAST THE FANS ON MAX"
 

mikeboss

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I will give disabling turbo a shot, thank you. Do you have a 2017 i7 btw?
nope. as I wrote already, I had an i7 (2017) on my desk for one weekend. I installed/migrated stuff onto this machine for one of my customers. that's when I decided to get an i5 because of the fan on the i7 ramping up constantly. but I wanted to get the 2017 model because of the image retention issue.
 

thefriendshipmachine

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Original poster
Apr 14, 2017
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nope. as I wrote already, I had an i7 (2017) on my desk for one weekend. I installed/migrated stuff onto this machine for one of my customers. that's when I decided to get an i5 because of the fan on the i7 ramping up constantly. but I wanted to get the 2017 model because of the image retention issue.
yes I am still hoping you are right that the 2017 has no image retention.... man I cant believe how many problems new iMacs have. I have a white 2007 C2D iMac sitting on my desk and it runs just like the day I got it.
 

joema2

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I owned a 2015 i7 iMac for two years and I had the 2017 i7 on my desk for a whole weekend...
I had 2015 and 2017 i7 iMacs side-by-side running tests and identical production loads for months. I observed no marked difference in thermal or fan behavior, even when under identical heavy loads. This is consistent with what other people have reported who tested them simultaneously side by side under controlled conditions.

....transcoding with FCPX: bear in mind that newer machines have Intel Quick Sync Video. that's why a newer model will encode two times as fast...
Actually all iMac 27s since 2011 (Sandy Bridge) have had Quick Sync. My comparison was between the 2015 and 2017 i7 iMac. It is true the 2017 uses Kaby Lake and that has a newer version of Quick Sync vs the 2015 Sky Lake but nobody knows for sure if that's why it's so much faster at transcoding 8-bit 4k H264 in FCPX than the 2015 model.
 

thefriendshipmachine

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Original poster
Apr 14, 2017
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hmm... disabling turbo caused the imac to last 20 seconds running the "yes" command before hitting 90C+ on all cores. I don't understand because the fan stays at 1200RPM the entire time. My 2014 iMac would've gone up to 2000RPM plus. Is there any way to make the fans naturally more aggressive? There's no way they should just sit at 1200RPM when all four cores are at 90C...
[doublepost=1514306095][/doublepost]
I had 2015 and 2017 i7 iMacs side-by-side running tests and identical production loads for months. I observed no marked difference in thermal or fan behavior, even when under identical heavy loads. This is consistent with what other people have reported who tested them simultaneously side by side under controlled conditions.

Actually all iMac 27s since 2011 (Sandy Bridge) have had Quick Sync. My comparison was between the 2015 and 2017 i7 iMac. It is true the 2017 uses Kaby Lake and that has a newer version of Quick Sync vs the 2015 Sky Lake but nobody knows for sure if that's why it's so much faster at transcoding 8-bit 4k H264 in FCPX than the 2015 model.
Do you mind running the terminal command "yes" and reporting back with your CPU temps and fan speed after 20 seconds or so? I'm trying to figure out if I'm experiencing normal behaviour or if I need to send back this Mac.