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cooling the iMac
- Thread starter zoran
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The case on the iMac is aluminum, and will radiate heat from inside your iMac. That's a Good Thing™. It will be warm, maybe hot in spots, but also means that the heat is making its way out. Running the fans at a higher speed manually can help out, too.
Not sure if a fan-control app is a good idea, or a bad idea. It's a utility which allows you to control the fan speed, should you feel the need to do so. So, neither a good nor bad idea, just a personal choice.
But, then a 10 year old iMac could probably use a "re-pasting" of CPU/GPU heat sinks, which can be helpful if the iMac runs hotter now than you think should be normal. That would also mean that your iMac would be disassembled, and cleaning the various cooling inlets/outlets would also be a good result of all that work (2-3 hours for that kind of job, I suppose)
If you can put up with the extra noise from fans running at a higher speed, then do it.
Not sure if a fan-control app is a good idea, or a bad idea. It's a utility which allows you to control the fan speed, should you feel the need to do so. So, neither a good nor bad idea, just a personal choice.
But, then a 10 year old iMac could probably use a "re-pasting" of CPU/GPU heat sinks, which can be helpful if the iMac runs hotter now than you think should be normal. That would also mean that your iMac would be disassembled, and cleaning the various cooling inlets/outlets would also be a good result of all that work (2-3 hours for that kind of job, I suppose)
If you can put up with the extra noise from fans running at a higher speed, then do it.
I use (depending on the situation, and the Mac) either smcFanControl, or Macs Fan Control.
There's probably a couple of others, but I have never looked for others.
Both are free to use.
Macs Fan Control has a "pro" version that adds custom fan presets to that app.
There's probably a couple of others, but I have never looked for others.
Both are free to use.
Macs Fan Control has a "pro" version that adds custom fan presets to that app.
I just replaced the iMac's graphics card, so now im being extra cautious with everything that i can. I know i might be overreacting but the the graphics card failure did shock me.
Run a fan harder than it has to and it will need to be replaced sooner.
Every Mac has temperature sensors that monitor conditions and report to the OS. The OS then controls the fan speed based on that information. Who knows how much engineering time goes into optimizing the automatic fan control... And then people think that somehow, they will do a better job of it - that they will actually notice when it's time to turn the fan speed up, and when it's OK to dial it down again. As if they're not busy doing other things.
A little warmth is natural and expected. That's what happens when electrons move around. The more work that's being done, the warmer it will get.
I wonder how many people turn their furnaces or air conditioners off/on manually, and how many allow the thermostat to do the work?
Every Mac has temperature sensors that monitor conditions and report to the OS. The OS then controls the fan speed based on that information. Who knows how much engineering time goes into optimizing the automatic fan control... And then people think that somehow, they will do a better job of it - that they will actually notice when it's time to turn the fan speed up, and when it's OK to dial it down again. As if they're not busy doing other things.
A little warmth is natural and expected. That's what happens when electrons move around. The more work that's being done, the warmer it will get.
I wonder how many people turn their furnaces or air conditioners off/on manually, and how many allow the thermostat to do the work?
If you still have a standard hard drive in it I would run a fan app. There is a lot of heat build up in those things and I cooked 3 HDs in my mid-2007 iMac.
(Same iMac with a SSD is sitting in my daughters room for school zoom calls)
(Same iMac with a SSD is sitting in my daughters room for school zoom calls)
Definitely use a fan app to monitor your temps and definitely run your fans according to your temps/processes.
Apple really dumbed down the rpm speed of the fans in order to keep the system quiet for a more pleasant user experience.
@zoran, I hope you gave the imac a good clean out as a 2010 imac will have 11 years of dust and fan grit build up that will inhibit the cooling system, I also hope you left the dvd drive installed so as the gpu will be efficiently cooled from the optical fan.
Apple really dumbed down the rpm speed of the fans in order to keep the system quiet for a more pleasant user experience.
@zoran, I hope you gave the imac a good clean out as a 2010 imac will have 11 years of dust and fan grit build up that will inhibit the cooling system, I also hope you left the dvd drive installed so as the gpu will be efficiently cooled from the optical fan.
Internally: Use Mac Fan Control app, if you can stand the fan noise, crank it to the highest speed.
Externally: Use the room Air Conditioner. Lower down the temperature.
IMO the Mid-2010 27" is a thermal nightmare. The design emphasizes quietness over longevity. I did a write-up on mods I made to the fans:
2011 27" iMac SSD upgrade + fan speed - Whats the current consensus? | Page 2 | MacRumors Forums
In the end, I changed to a 240G x 2 SSD RAID 0 setup. My motivation was to rid the system of any mechanical drive that makes seek noise (the iMac is in my bedroom). However, only SSDs live well at such high temperatures. Before the change I had a 240G SSD + 12TB HDD fusion drive setup, and I tried hard to keep the HDD temperature under 47 degrees. The fan goes up much of the time, making it noisy, and I had to fiddle with Macs Fan Control a lot to balance between temperature and noise. Now I don't need to worry any more. My SSDs stay cool because there is much room for air to circulate now and going above 50 degrees for solid state components is not a concern.
2011 27" iMac SSD upgrade + fan speed - Whats the current consensus? | Page 2 | MacRumors Forums
In the end, I changed to a 240G x 2 SSD RAID 0 setup. My motivation was to rid the system of any mechanical drive that makes seek noise (the iMac is in my bedroom). However, only SSDs live well at such high temperatures. Before the change I had a 240G SSD + 12TB HDD fusion drive setup, and I tried hard to keep the HDD temperature under 47 degrees. The fan goes up much of the time, making it noisy, and I had to fiddle with Macs Fan Control a lot to balance between temperature and noise. Now I don't need to worry any more. My SSDs stay cool because there is much room for air to circulate now and going above 50 degrees for solid state components is not a concern.
You have 3 fans: CPU, hard drive, and Optical drive. The optical drive fan also provides airflow through the GPU heatsink.
But, the big heat producer will probably be the CPU.
If you "feel around" on the back when it is hot, you can localize the hottest area. It will probably be on the left back side (in the area of the CPU heat sink)
Fan control apps will also show you the temp of the sensors that control the fans. You can also use an app like HWMonitor, that can display ALL the various sensors in your 2010 iMac, and you can see exactly what is generating heat. You will also be able to see that the fan speeds actually increase. A fan control app lets you increase speed on one fan, or some combination of fans, if that works out better for you.
hmm... near 12 years old, if there is more heat produced than you have seen before, it's probably time to repaste both the CPU and GPU heat sinks.
But, the back of the iMac is all aluminum, which is a pretty good heat sink. If you can feel hot areas, the case is doing its job. Adjust the fan speeds up, if you like - BUT also make sure that the airflow is not obstructed. You will have to take things apart a lot to inspect everywhere.
But, the big heat producer will probably be the CPU.
If you "feel around" on the back when it is hot, you can localize the hottest area. It will probably be on the left back side (in the area of the CPU heat sink)
Fan control apps will also show you the temp of the sensors that control the fans. You can also use an app like HWMonitor, that can display ALL the various sensors in your 2010 iMac, and you can see exactly what is generating heat. You will also be able to see that the fan speeds actually increase. A fan control app lets you increase speed on one fan, or some combination of fans, if that works out better for you.
hmm... near 12 years old, if there is more heat produced than you have seen before, it's probably time to repaste both the CPU and GPU heat sinks.
But, the back of the iMac is all aluminum, which is a pretty good heat sink. If you can feel hot areas, the case is doing its job. Adjust the fan speeds up, if you like - BUT also make sure that the airflow is not obstructed. You will have to take things apart a lot to inspect everywhere.
They come from all of the parts
LCD is an old panel, always hot if you keep it at high brightness.
PSU is 310W, efficiency is about 85%, the rest is heat. Check PSU temperature on HWinfo, Istatmenu or Mac FanControl. Too hot PSU and it will fail soon.
CPU is first gen core i, TDP 75W.
GPU producing heat, too.
All of them are trapped inside the aluminum case of the iMac. The case does a very good job of dispersing heat to ambient environment. When you touch the top edge and feel hot, it means the fans are working fine and blowing heat out of the iMac from its top vent.
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It's not that bad. lol. It's 'thermal nightmare' when compared to desktops in general. But for AIOs, the aluminium unibody design is the pinnacle of a traditional computer (+HDD, ODD, dGPU, DIMMs) that perhaps will never be surpassed IMO. I've been using my iMac for 10 years but only in later years and after inspecting the internal closely, I started to appreciate its thermal design. Nothing major failed in my machine but the original HDD died at 7.5 yr point. I felt sorry for its premature death due to heat. And the heat was mostly due to my ignorance that I realised a year or so after its death.
I did my first deep cleaning early this year, including re-pasting CPU, GPU, PCH chip. That's in addition to de-dusting fans (except the HDD fan behind the Logic Board) a few times in previous years. I found the condition of CPU and GPU and their TIMs in pretty good shape after so many years! So contrary to common belief, after the deep cleaning, I didn't see a significant difference in temperatures at idle or medium workloads except the PCH. CPU & GPU are about 2-3C lower. At extreme workloads i.e. 100% AVX on all cores + 100% GPU load, CPU does show noticeable improvement with a much (i.e. >2-3C) lower maximum heat-saturated temperature. For GPU at extreme, again noticeable thermal improvement but I did a few MODs in addition to re-pasting the die. So not sure how much re-pasting contributed.
The PCH chip is a poor guy. Apple used CHEAP white glue/paste as TIM. Apple also put on a cheap heatsink. This explains the notoriously high temperature for the PCH that's already hot to begin with. Re-pasting the PCH alone keeps its temperature to below 60C most of the time. If it's not such an old machine, I would probably find a better replacement heatsink too. I regretted a bit I didn't re-paste the VRM next to CPU since I'm sure Apple used the same cheap paste there. Most likely the same for the Thunderbolt chip but I don't care as the first gen thunderbolt is practically useless from the start, and hot as hell anyway.
So folks, watch out if you're planning a thorough re-paste work.
47C is an interesting number. I wonder how did you come up with this threshold.
So after my original HDD died, I figured the best thing to fill the 'gigantic' empty space is nothing but a new & large HDD (since I already have a SSD beneath the optical drive). For close to a year, I used a commonly recommended 3rd-party app to control the HDD fan. I was not happy with these apps. So I wrote my own little software and a custom fan curve. Yay, better acoustics and temperature finally. In summer, it struggled a bit occasionally.. to keep the temp below 50C at idle without roaring a 70% full blast. So during the deep clean, I decided to glue a few heatsinks on both sides of the HDD. Unfortunately the ones I bought only made their way to the front of the drive (not at the same time the back of the drive facing the iMac back cover). Anyway, thermal reduction is already noticeable. Ever since, I haven't seen it hitting 50C at idle or medium workloads. Usually it's hovering around 46-47C with an ambient temperature of 30C.
Here are the typical temperatures of this iMac at idle:
For OP & folks planning to use 3rd-party apps to control fans, be prepared to manually intervene a few times per day. lol
As an aside, worth pointing out, IMO, Apple's algorithms behind the fan curves are surprisingly well thought out. I tried to mimic similar behaviour in BIOS settings of my Linux PC. It simply can't come close.
By months of fiddling LOL. Specifically I aim for 2,200rpm (which I found barely audible) when not under load.
Google did a study of annualised failure rate and found the optimal temperature to be 37 to 46.
Now I ran 2 SSD's in RAID 0 and I don't worry about heat any more, and it's at the lowest fan speed of 1,100 all the time. Just old SSD's from years ago.
Very interesting data point. So looks like my after-market heatsinks help quite a bit, maintaining similar temperature at 18% less rpm.
Perhaps useful to other folks. 2200rpm is very quiet to my ears too. Even 2800rpm is acceptable to me at late night. I think people can find better replacement fans if they look harder or improve the sturdiness of the existing assembly to eliminate rattling at high speed.
Two SSDs to fill up the 'gigantic' drive bay would also be very appealing to me if I had not done the SSD behind the optical drive in early years. So I continued with a new HDD to make it click, offering a sense of fullness. I also won't forget to regularly clean the fan grill at the back of iMac. I believe seven years of dust there basically cooked my original HDD to death in its final years.