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Cruciarius

macrumors regular
Original poster
Aug 18, 2013
109
17
Massachusetts
So I've been roaming these forums more often recently, due to my late 2014 iMac 5K (27-inch, maxed RAM, i7) overheating + being interested in the 2018 Mac Mini. Due to me having said iMac repaired before for hardware issues, I was under the assumption the issues were just coming back and with it not under warranty, I've been very interested in the Mac Mini.

Yesterday, someone in the Mac Mini forums told me something. Running the iMac in scaled resolution can be the problem. On a whim, I tested it and it seems they were right. I'm basically addicted to watching people stream on Twitch. I typically have anywhere from 2-5 streams open at any given time. Prior to the resolution suggestion to me, I was running the iMac at a scaled resolution of 3,800 something by... I don't know what. It's the 2nd option down in the scaled resolution options. The reason I was running it with that is due to more desktop space. I like having more space. More windows. Not having to scroll as much. Turns out, that was the issue. Changing back to the default resolution seems to have solved my overheating issues. Or at least, I think so. Managed to have 5 Twitch streams open last night while staying just around 200° F. With the scaled resolution, I'd have been reaching close to the force sleep of 225° F. Plus the fan wasn't going crazy, like it would with the scaled resolution and only 2 or 3 streams open.

Now to my question... I really want that more space I had before. Already running a 2nd monitor (a 27-inch 1080p) with no place for a 3rd. While I haven't tested the iMac for gaming again yet, I'm wondering what my options are to get more screen space, without taking up more desktop space (3rd monitor, although I have no room for it anyway). Would the Mac Mini be a viable option with 2 4K monitors? Do I have any other options to have more screen space with my current iMac?
 
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As you appear to be running multiple videos per screen, you could have a third screen if you rotate your second and third screens into portrait mode. Two portrait screens will take up only a small amount more of desk space compared to one screen in landscape.
 
Well I thought my iMac running in the "Default for display" fixed the over heating issues I was having, but no. Today I had only 1 Twitch stream open on the 2nd display and tried to play a game on the iMac display. It quickly reached the 225°+ F and went into forced sleep.

Prior to these issues, I used to play Diablo 3 and listen to iTunes, while also having 1-2 Twitch streams open.

are you planning to use an egpu?
Yes, I would get an eGPU for the Mac Mini.
 
Well I thought my iMac running in the "Default for display" fixed the over heating issues I was having, but no. Today I had only 1 Twitch stream open on the 2nd display and tried to play a game on the iMac display. It quickly reached the 225°+ F and went into forced sleep.

Prior to these issues, I used to play Diablo 3 and listen to iTunes, while also having 1-2 Twitch streams open.


Yes, I would get an eGPU for the Mac Mini.
Considering that your overheating problems originated while under warranty then any repairs may still be treated as warranty repairs. Since it is a defect that was only temporarily solved while under warranty you may be entitled to a warranty replacement. Also if you plan on throwing it away then you can throw it my way in order to avoid it ending up in a landfill.
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Well I thought my iMac running in the "Default for display" fixed the over heating issues I was having, but no. Today I had only 1 Twitch stream open on the 2nd display and tried to play a game on the iMac display. It quickly reached the 225°+ F and went into forced sleep.

Prior to these issues, I used to play Diablo 3 and listen to iTunes, while also having 1-2 Twitch streams open.


Yes, I would get an eGPU for the Mac Mini.
Planting it in front of an air conditioner vent may help negate the heating. Additionally a 3rd party computer repair technician may be able to fix it using a better quality thermal paste.
 
@borgranta - When I do replace the iMac, I'm going to aim to get the most I can with a trade-in price for it, thru Apple. Looking thru the Q&A for such a process, it asks about the OS operation, if the computer boots up, and if it has any visible damage. All of which is fine, aside from the over heating. The overheating is likely a hardware problem that isn't asked during those questions, so as far as I'm concerned, it's going to be worth the full trade-in value of over $700.... sad with how much I paid when the thing was brand new in 2014.

Even if I decided to not trade it in & instead give it to someone else, I'd likely just give it to my parents. They have an old eMac that is super outdated. They might have no real issues with the iMac though, since all they do is emails and some spreadsheet work.

Looking at another thread about a 2017 iMac (the 7TB iMac thread) and seeing that that machine is normally at 30° C (80° F) and mine runs roughly 100° F more than that, really worries me. Back when I got the iMac, I never thought to keep an eye on the temp. Wasn't until after my issues came to be that I got iStat Menu to see it. Wish Apple had a built-in method of seeing the temps.

@MandiMac - The fans can be heard just fine when it gets around 180-190° F. Nothing blocking the vents. Not against a wall. Nothing other than an Apple Superdrive sitting on the foot of the iMac, so plenty of clearance there.
 
So I have enough to buy the Mac Mini now, but before doing so, I did some testing with the iMac.

Booted into safe mode, with no USB devices, other than mouse & keyboard. Noticed in safe mode, 2nd display doesn't get used, btw.

I did open up iStat Menus to watch temps. Nothing else was running. Just the safe mode boot, so just the Finder was open, I opened 2 Finder windows. Was moving around some files, just to clean up some folders while watching the temps. Doing this, GPU Die stayed around 140° F and fans were around 1400 RPM.

After that test, I shut down and did a NVRAM reset as well as a SMC reset. After booting up normally, I have iStat Menu, Discord, and Twitterrific open. GPU Die temp is now at 180-190° F and fans high 1400 RPM to low 1500 RPM.

Unplugged the 2nd display and the GPU Die is down to around 150° F and fans around 1200 RPM.

Makes sense to have temps increase with a 2nd display, but is it normal? It's currently connected via an HDMI to a display to HDMI adapter (the iMac has no HDMI port). I've searched Google & saw others reporting overheating with various Macs with a 2nd display over HDMI, but I don't know of any other way to connect it & none of them had a solution.

Are my issues normal for an iMac trying to use a 2nd display? 2nd display being a 1080p resolution, btw. I really prefer having 2 monitors, so I need to either find a fix for this or just buy the Mac Mini, which I assume would handle 2 monitors better, with an eGPU.
 
So I have enough to buy the Mac Mini now, but before doing so, I did some testing with the iMac.

Booted into safe mode, with no USB devices, other than mouse & keyboard. Noticed in safe mode, 2nd display doesn't get used, btw.

I did open up iStat Menus to watch temps. Nothing else was running. Just the safe mode boot, so just the Finder was open, I opened 2 Finder windows. Was moving around some files, just to clean up some folders while watching the temps. Doing this, GPU Die stayed around 140° F and fans were around 1400 RPM.

After that test, I shut down and did a NVRAM reset as well as a SMC reset. After booting up normally, I have iStat Menu, Discord, and Twitterrific open. GPU Die temp is now at 180-190° F and fans high 1400 RPM to low 1500 RPM.

Unplugged the 2nd display and the GPU Die is down to around 150° F and fans around 1200 RPM.

Makes sense to have temps increase with a 2nd display, but is it normal? It's currently connected via an HDMI to a display to HDMI adapter (the iMac has no HDMI port). I've searched Google & saw others reporting overheating with various Macs with a 2nd display over HDMI, but I don't know of any other way to connect it & none of them had a solution.

Are my issues normal for an iMac trying to use a 2nd display? 2nd display being a 1080p resolution, btw. I really prefer having 2 monitors, so I need to either find a fix for this or just buy the Mac Mini, which I assume would handle 2 monitors better, with an eGPU.
The going rate for your model of iMac is far more reasonable on Ebay than what is offered by Apple. Since it is working when not using a second screen you may be able to sell it to someone that has no desire to use extra screens. Also if you are wary of dealing with EBay buyers you could instead use it as a secondary computer to do light tasks use the Mac mini as the workhorse
 
Going thru Apple's questions on trading this iMac in, it never asks about the hardware. Just visible damage, if it turns on, and if the OS itself runs correctly. Never asks about fans and overheating, so with that, Apple would pay me $770 for it. With eBay, I wouldn't mind selling it there, but I lack a box for it. I've seen nightmare unboxings of iMacs bought on eBay before. Plus I'd be completely honest about it in the description, so I'm unsure anyone would be interested in it with that issue or even try undercutting my asking price.

I see on Apple discussion boards that a late 2014 iMac SHOULD be able to run it's own display at 5120x2880 along with a 2nd at 3840x2160. I had to drop mine down to "default for display", which is only 2560x1440, in order for me to even run a 2nd monitor without it's forced sleep. Imagine if I did try running this iMac at max resolution + get a 4K display, I might cause it to explode. lol

So... I think I'd rather trade this in for what I can now, which cuts the Mac Mini cost nearly in half (I'd get the upgraded processor and 512GB SSD).

Guess after posting the above post, then doing some Google searching & seeing what I should be able to run this with, I'm pretty set on ordering the Mac Mini.
 
How do you have the external monitor hooked up?

Expect more heat just by having it plugged in. Expect a lot more if you are using the external for the twitch streams.

The GPU just isn't as efficient at running an external as it is the internal.

Connecting my MBP (integrated graphics) to a Dell 1080p monitor I will see 20-30c increase in temps. If I move a video too the external 30-40c increase. If I connect my MBP to a 4k display and stream a 4k video to it I'll see 100c CPU temp.

Adjusting resolution down on the external (decrease the workload) is really the only thing you can do.
 
The 27" iMacs have an airflow/dirt problem. Here's mine just two years out of Apple Store HD replacement. I'm sure they cleaned it then...Maybe not. A2
IMG_1665 (2) copy.jpg
 
How do you have the external monitor hooked up?

Expect more heat just by having it plugged in. Expect a lot more if you are using the external for the twitch streams.

The GPU just isn't as efficient at running an external as it is the internal.

Connecting my MBP (integrated graphics) to a Dell 1080p monitor I will see 20-30c increase in temps. If I move a video too the external 30-40c increase. If I connect my MBP to a 4k display and stream a 4k video to it I'll see 100c CPU temp.

Adjusting resolution down on the external (decrease the workload) is really the only thing you can do.
Actually, when I drag a Twitch stream window from the iMac screen over to the 2nd screen, the heat decreases.

The 27" iMacs have an airflow/dirt problem. Here's mine just two years out of Apple Store HD replacement. I'm sure they cleaned it then...Maybe not. A2View attachment 822271
You have no idea how stupid I feel. On Sunday, I unhooked the iMac and vacuumed it off. Dusted it too. Dusted my desk as well. Such a pain trying to get my vacuum in behind the stand of the iMac, to vacuum off the vents. Once all hooked up again, it actually seems to be running MUCH better. I even tried to stress test it with various software all running at once. Things like 3 Twitch streams, OBS, a game, iTunes, and more. While it did hit that 225° F temp occasionally, the fans ramped up to keep it from going into forced sleep.

So... I THINK it's fixed. With all that done though, I did notice that with all that running, typing was a pain. I could type out a sentence, then watch as it actually appeared into the text field. So while I think it's fixed, I still might replace it with a Mac Mini, since those are still more powerful than my 2014 iMac.
 
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