iMac Retina Heat management

[Cameryn12]

Yeah. I thought he was providing good info, but now that I see how many times he's posted the same info it makes me think he never owned the imac.

Oh please - yes, I did, and was crushed when I had to return it. I don't have an agenda other than the fact that I'm extremely concerned about this GPU heat thing, and what shocks me is that the rest of you aren't. But I'm sure you'll conveniently forgive Apple, when there are complaints about this GPU frying people's motherboards. Have fun with that.

 

[DerekS]

There is no "heat management issue." You're being ridiculous.

How can you expect the machine to push so many more pixels than the last one without generating more heat? Of course it's going to generate more heat.

The fact of the matter is the machine stays quiet and well behaved under normal use. It only spins up the fans when pushed, which is what it's supposed to do.

 

[DerekS]

Oh please - yes, I did, and was crushed when I had to return it. I don't have an agenda other than the fact that I'm extremely concerned about this GPU heat thing, and what shocks me is that the rest of you aren't. But I'm sure you'll conveniently forgive Apple, when there are complaints about this GPU frying people's motherboards. Have fun with that.

Don't you think it's kind of silly to be "extremely concerned" about an issue that:

- Causes no operational problems
- Is fully covered by warranty for a year
- Can be extended to 3 years with Applecare?

 

[goodcow]

Don't you think it's kind of silly to be "extremely concerned" about an issue that:

- Causes no operational problems
- Is fully covered by warranty for a year
- Can be extended to 3 years with Applecare?

Three years on a machine at this cost isn't sufficient. Apple should offer the four-year AppleCare option reserved for Education customers (non-end user) to home users as well.

 

[Rocinante2000]

Ok, I have to chime in here.

The fans are going to come on, they may get noisy but they have to spin to move air, its just such an important task. If you want a silent computer, please get one but this iMac regardless of debates about the power of the GPU is an incredible technological achievement and has to get rid that hot air moving to protect its hardware I am glad it does.

I have spent the last 25 years running a technology consulting company, I have 3 large plastic bins you get from Walmart to store your goods filled with 90% nVidia based HP laptops that opted for a less efficient but more "quiet" cooling fan. Guess what happened? The heat stayed in the chassis and the solder on the GPU started failing creating microscopic bubbles and breaking the solider joints. Now please don't read this as an nVidia bash, its not, its a "lets make a quieter computer but sacrifice longevity" pointing finger at HP.

This happened because when motherboards/circuitry get hot, they start to soften, then over time they start to warp. This then creates a stress from the heat-sink pulls the component in one direction and the socket another and these solder imperfections appear. To add to this European Union banned lead in solder many moons ago so before solder would stretch, now it cracks resulting in a fail. I have re balled MANY GPU's and CPU's using better solder and the problem is solved for the most part, but I digress.

The technology that is inside of these devices from Macs, to PCs, to game consoles absolutely have to move hot air out of the system. I believe Apple do one of the better jobs at thermal dynamics in the industry. I am not even a "Apple Fan boy", I am a technology fan boy.

Bottom line, this post isn't to troll or to create drama, but please lets be realistic here, the fan is going to ramp, and when you move fan blades it creates turbulence which makes noise. The tech inside these things is just insane.

 

[magbarn]

Blame it on the A8 and A8x consuming all of TSMC's 20nm production lol. In all seriousness, I can't believe we're still stuck with hot GPU's made with 4 year old 28nm TSMC tech when we should've already transitioned to much cooler and efficient 20nm node process.... I'm not upgrading any of my Apple dGPU machines (2012 27 iMac/2012 rMBP 15) until a proper 20nm GPU is put in one.

 

[Col Vandal]

Blame it on the A8 and A8x consuming all of TSMC's 20nm production lol. In all seriousness, I can't believe we're still stuck with hot GPU's made with 4 year old 28nm TSMC tech when we should've already transitioned to much cooler and efficient 20nm node process.... I'm not upgrading any of my Apple dGPU machines (2012 27 iMac/2012 rMBP 15) until a proper 20nm GPU is put in one.

And where are these available for Apple to use?

 

[macmee]

Here's my temps, I'm running a 4k monitor, doing stuff in xcode and I've been in a google hangout all day:

I can't hear my fan, so I'm assuming it's OK for the GPU die to be at 100C.

edit: look at my rMBP's temps, higher but not red. Curious...

 

[FredT2]

Here's why the fans run

Someone in another thread posted this link to iMac power consumption and thermal output chart.

http://support.apple.com/kb/ht3559

It shows why the i7/295x combination has the fans running more: it puts out 50% more heat at maximum load than the lower spec model. It actually puts out a little more heat than the 12-core Mac Pro!

http://support.apple.com/kb/ht2836

In practice I haven't been able to get it over about 230 watts pushing both the CPU and GPU. Running Unigine Heaven gets it up to 175 watts, which is almost all from the GPU. And though the chart says it idles at 70 watts, I measure it only 35 watts.

 

[vir3l]

Here's my temps, I'm running a 4k monitor, doing stuff in xcode and I've been in a google hangout all day:

Image

I can't hear my fan, so I'm assuming it's OK for the GPU die to be at 100C.

edit: look at my rMBP's temps, higher but not red. Curious...

very interesting. what is your cpu and hd?

your fan is at 1500 rpm with gpu diode at 100 C.
my fan is at 2700 rpm with gpu diode at 100 C.
my system is 5k imac, i7, m295x, ssd running os x.10.

if yours is the same, i think we DO have a fan issue, ceteris paribus.

 

[xgman]

The AMD GPU runs hotter and draws more power than the equivalent Nvidia mobile chip.

Then it is too bad that Apple didn't stick with Nvidia this time around, I as afraid of this. It's not the end of the world, but you do have to get used to it if you are accustomed to rarely hearing the fan spin up like on my old 2012 680x imac. In my case, I think the 4ghz cpu is also making the fan spin up more.

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On my old 2011 iMac I used a fan program called SMC fan control which allowed the user to manually control the fans and I found having the fans on very low all the time was better than having them cutting in/out all the time.

I assume that SMC is no longer an option in that way for the 2014 models?

 

[5iMacs]

very interesting. what is your cpu and hd?

your fan is at 1500 rpm with gpu diode at 100 C.
my fan is at 2700 rpm with gpu diode at 100 C.
my system is 5k imac, i7, m295x, ssd running os x.10.

if yours is the same, i think we DO have a fan issue, ceteris paribus.

What if he is running with a lower CPU load and the iMac is being very accommodating and only ramping up the fan when it is near 100 degrees?

on my i5/M290X it lets the CPU max out at full load at 86 degrees (with a very low fan), it doesn't try to keep it cooler even though it easily could by raising the fans to an audible level

 

[joema2]

....the i7/295x combination...puts out 50% more heat at maximum load than the lower spec model...

Note if compared to the top-spec 2013 iMac 27 with nVidia GTX-775m, it only puts out 25% more heat at max load. That includes moving from a 3.4Ghz i7 to a 4Ghz i7, so the CPU alone probably accounts for some of this.

At least the top-spec retina iMac puts out 21% less heat than the 2010 iMac which was 365 watts.

 

[macmee]

very interesting. what is your cpu and hd?

your fan is at 1500 rpm with gpu diode at 100 C.
my fan is at 2700 rpm with gpu diode at 100 C.
my system is 5k imac, i7, m295x, ssd running os x.10.

if yours is the same, i think we DO have a fan issue, ceteris paribus.

Same system as you. The question is, why is my fan not running faster if the diode is at 100c?

 

[steve62388]

Same system as you. The question is, why is my fan not running faster if the diode is at 100c?

Ambient air temperature?

 

[vir3l]

good point, between 20-25 C. will check

 

[macmee]

good point, between 20-25 C. will check

Same here

 

[Onimusha370]

Here's my temps, I'm running a 4k monitor, doing stuff in xcode and I've been in a google hangout all day:

Image

I can't hear my fan, so I'm assuming it's OK for the GPU die to be at 100C.

edit: look at my rMBP's temps, higher but not red. Curious...

what program are you monitoring the temps on?

Thanks

 

[macmee]

what program are you monitoring the temps on?

Thanks

iStat

 

[xgman]

iStat

you mean iTakoeoveryourcomputer hate that app.

 

[tillsbury]

Here's my temps, I'm running a 4k monitor, doing stuff in xcode and I've been in a google hangout all day:



I can't hear my fan, so I'm assuming it's OK for the GPU die to be at 100C.

edit: look at my rMBP's temps, higher but not red. Curious...

You sure you're not in Fahrenheit on the right there? My rMBP never hits 90C...

 

[ha1o2surfer]

Is that iMac running at 75-80c while the CPU is only drawing ~45 watts? wow... that's horrible lol

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There is no "heat management issue." You're being ridiculous.

How can you expect the machine to push so many more pixels than the last one without generating more heat? Of course it's going to generate more heat.

The fact of the matter is the machine stays quiet and well behaved under normal use. It only spins up the fans when pushed, which is what it's supposed to do.

The poster that said running the CPU and GPU under full load made the benchmark choppy and both chips were running at 100C.... yes that is a heat management issue for sure lol

 

[DerekS]

The poster that said running the CPU and GPU under full load made the benchmark choppy and both chips were running at 100C.... yes that is a heat management issue for sure lol

Fine, don't buy one then. I think you're being stupid.

In the meantime, I will continue LOVING mine!

 

[macmee]

I think I've figured it out.

If I'm in a Google Hangout and keep the tab open (so that I can see the other participants) then my GPU diode rockets to 100C. If I stay in the hangout but keep it in a background tab, I get these temps:

I'm going to install League of Legends now and try playing it, will report back later with diode temps (can any other riMac owners confirm that their diode gets this hot when gaming/ghangouts?).

Is that iMac running at 75-80c while the CPU is only drawing ~45 watts? wow... that's horrible lol

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The poster that said running the CPU and GPU under full load made the benchmark choppy and both chips were running at 100C.... yes that is a heat management issue for sure lol

Why is it horrible? It's Google Hangout's fault.

You sure you're not in Fahrenheit on the right there? My rMBP never hits 90C...

It's in Celsius. My rMBP runs cooler too, but we're comparing apples to oranges.

 

[ha1o2surfer]

I'm not saying don't not enjoy it.. for most people, this issue wont happen. We like to test things because we are curious or we are the folks that play games that require heat to be under control. If you do basic things like Lightroom, browse the web and such then you won't notice it

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Why is it horrible? It's Google Hangout's fault.

Well I just would have thought the iMac would keep the CPU cooler while it's not working very hard, that's all.

It's all about the headroom, that is what's important. If you're just browsing the web and the GPU is sitting at 77c..... doesn't leave much room when the GPU is using another 80 watts while it's under a full load don't ya think. Throttling has to happen pretty soon.

ORR iStat doesn't fully support the riMac yet