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Aluminium iMacs overheating?

I've just been running SL for a while with the fans at "default" (no acceleration) and although a couple of textures flicked slightly while the surrounding objects were loading, this seemed normal as part of the loading process (textures load progressively etc) and I couldn't reproduce the flickering from last time.

I think perhaps it's a bug with SL... wouldn't surprise me, it's an extremely buggy app, it always has been. Perhaps I was just panicking over nothing because the casing on the top-left gets quite toasty (sounds like this is normal?)

Ideally, some kind of GPU stress tester would be nice. It's handled WoW just fine (under OS X) as well as EQ and EQ2 and even a brief foray into the graphically heavy Vanguard (under Windows) so there's hope yet :)
 
More tests - tortured the soul out of this poor thing - Apple Chess running Computer-vs-Computer *and* floating around on Second Life at the same time, this pushed both cores to a consistent 95-100% and probably pushed the GPU a fair bit as I was constantly flying around loading/rendering objects etc. Saw the CPU fan ramp up to 1760RPM, couldn't get the temperature past 59C no matter what I tried (which is good! IIRC temps don't have any real impact on lifespan until 75-80C or so, and are not "damaging" until 100ish).

Tried quitting smcFanControl and doing a sleep-wake cycle (which removes any minimum speed it had set) even though it was set at default already, just in case it was having an effect still, and ran with that for 10-20 mins. Still fine. Launched it again and observed that temp was 58C and fan speed ~1700RPM, immediately, so obviously it's adjusting just fine without it.

By this point the casing at the top-left is *very* toasty, but CPU temp still under 60C so obviously the case just acts as a very good heat dissipator. Aluminium FTW :) I can see why they're converting everything to it.

At this moment in time it's sitting at 54C, 1215RPM with SL in the background still behaving CPU at 45% (Chess has finished again), haven't seen any of the weird flickering through any of this, even on the same bit of land I was experiencing it when I posted this thread. I'm now pretty well assured that it was just a glitch in the matrix. As I say, SL can be quite buggy (especially on ATI cards, I might add) so I'm not particularly concerned. And I can say "ya booo" to people who say I shouldn't be stressing the poor thing because I'm "not part of the intended audience" (bollox), I've abused it silly and it's held its own very well so far.

Still, I'm open for suggestions for a highly graphical game demo or something, anything that will push the GPU to its limits just to be sure.
 
So, Cloudane, you're saying that your iMac adjusts its fans without the help of smcFC. Right?

Maybe you could do what Barefeats did and run games and see their fps, only in your case, you could just have for about 1-2 hours and check your temperate and fan speed. Quake 4 on high quality?
 
Yes, it does indeed. As far as I can tell anyway... it's kind of "fridge light syndrome", you can't see what speed it's going at unless smcFanControl is open (I can't find any other fan monitoring apps?) but based on the temps after running without smc for a while I'd say so.

It doesn't go into "jet engine" mode like PCs etc often do when you push them, which I think is what I was expecting... having seen the actual temperature measurements though I can see that it doesn't need to. At 58C it's not necessary to go full tilt on the fans unless you get the burning desire (pun intended :p) to cool it down to 45 or so a bit quicker.

Think I was just panicking over nothing - combination of the one-off ground texture flicker in SL (which I haven't reproduced and only affected the bit of ground outside my house) and the fact that the casing gets very warm (seems to be by design) had me all paranoid :)

Still, will have a go at the Quake4 demo and see what happens just to be sure.
 
So far so good. The graphics in Q4 are quite nice, although it's odd that it doesn't do proper widescreen, the best I can manage is 1280x1024 which sits on the far left of the screen!

I'm hoping the fuzzing/shimmering "static" type effect on the green menu screen is normal, as well as some rough gradients there? It's perfect in-game so far anyway, just that menu screen kind of reminded me of the way Windows appears on this Mac.
 
What about everyone's HD temps. Ranges anyone??
With SMC on 2500 rpm mine range from 46 (idle) to 52 (large file transfers) Celsius. I do have the 750 Hitachi drive which supposedly runs somewhat warmer.

-Paul
 
What do you use as a monitoring app? As smcFanControl only seems to show CPU temps, not HDD or GPU.
Edit: n/m I googled for "mac temperature monitor" and found one aptly named "Temperature Monitor".

Current temps, pretty much idle (came out of Q4 about 20 mins ago):
Ambient 25, CPU heatsink 43, GPU chip 57, GPU heatsink 56, GPU diode 61, HDD bay 49, Memory 46, Optical 45, PSU 71 (!), HDD itself 49, Wireless module 65, both CPU cores 45.

I'm amazed at how many sensors are in this thing!! Wow! Ambient one too, no need to buy a separate temperature sensor for the room :p

That's pretty funny, the whole thing is sat around 45C, it's basically using everything right down to the optical drive as one big heatsink.

Just played through the Quake4 demo a few times, making up about an hour, no issues at all. In fact I'm quite surprised how smooth it is, though it's using the Doom3 engine which is quite old now... maybe there's something even more intensive I can push it with.

Edit 2: Just another update 15 mins later, I've now set smc to the often recommended 1500/2500/2000.
Amb: 24, CPU-HS 39, GPU chip 50, GPU HS 48, GPU diode 51, HDD 46, mem 42, Optical 41, PSU 57 (MUCH better!), wireless 59, cores 40.

Quite a plunge. I don't know if it's down to the higher fan speeds or just because it's been idle for longer. It's going to take a bit of experimentation... I think it's absolutely fine and certainly not doing any short term damage although I may run smc at these recommended settings in the long run just for peace of mind. I'd rather my Mac lasts 4 years than 2 :) I think the PSU would be the first thing to pop, at those temps.
 
ppolios said:
What about everyone's HD temps. Ranges anyone??
With SMC on 2500 rpm mine range from 46 (idle) to 52 (large file transfers) Celsius. I do have the 750 Hitachi drive which supposedly runs somewhat warmer.

-Paul
Click to expand...

Btw Cloudane, I never tried Temperature Monitor (I have heard of it) but have you tried iStat Pro? The widget, that is.

My current HDD temp (like 15 minutes after waking up and playing music on iTunes) is right now 39ºC.

Usually by the middle of the day when I start pushing it with games and prolonged use it goes up to around the high forties and stays there. With smc it stays in the low forties.

Oh Cloudane, might anti-aliasing might make a difference.
 
Thanks Leon/KJ will give those a go tonight. Good idea on cranking up antialiasing. I'd try CoD4 but the Mac version isn't out yet, I'd be looking to test things within OS X as Windows has graphical weirdness of its own (as does Linux, interestingly)
 
Hmm... At what temperature did your fans start rising? You sure it wasn't smcFC changing the speeds seeing that smcFC was on when you recorded the temps?

I'm not sure if encoding movies (using Handbrake) takes CPU or GPU but I been encoding about 2 movies (half way through 1 and 4 more to go) and my temperature looks pretty high, yet the fans speeds aren't changing. :confused:

(Well I think it works the CPU by the looks of iStat but my GPU temp is scaring me)...

EDIT: Finishing up that movie (from the time I took the picture) so 3 more to go!!! :D

Picture1-1.png


Picture2-1.png
 
vtprinz said:
The vast majority of iMac users are never going to push the graphics chip that hard, and the heat conductive abilities of the aluminum enclosure allow the machine to run (under normal circumstances) with minimal fan speeds.

I doubt it's a fault of apple in keeping the fans down, but rather more that you're just not the target audience, and the machine isn't specced for your demands. I know several gamers on the PC side that had to buy higher rated fans to put into their towers for this same problem. The only difference here is that you can't upgrade the iMacs fan, which is a shame, but being "all-in-one" is kind of the point of an iMac in the first place.
Click to expand...

I'm sorry. But I don't think cards should overheat from use. I think its just a fault of a setting/design somewhere. Since the design is technically still new.
 
Nichod said:
I'm sorry. But I don't think cards should overheat from use. I think its just a fault of a setting/design somewhere. Since the design is technically still new.
Click to expand...

Personally, I don't see it as a design flaw but more of a fault in the software maybe?

Not saying that OS X sucks or anything but something software side isn't telling the fan to increase speed as temperature goes up. If it does, then I would love to see a chart that shows the correlation between the temperature and the fan speed.
 
Here we go.... I reset smc to defaults, quit it, did a sleep/wake cycle and then did a power off and on cycle to be absolutely sure its influence was gone.

Then started up Chess and Second Life to give both the CPU and to a reasonable extent the GPU a good hammering.

At first it was heating and heating and staying at the default fan speeds of 1200/1200/1000. This was with the GPU heading to 60, PSU heading to the higher 70s and CPU towards the mid 50s. Then finally it started speeding up, proving that eventually it does so without the help of smc:

temp1.gif


temp2.gif


temp3.gif


temp4.gif


As you can see it seems to find a temperature it's comfortable with (CPU 55 etc generally) and gradually ramp up the fans to keep it at that upper "limit". These were taken over a 40 minute period, it seemed to settle at the status in the 4th reading, at least for a good 10+ minutes so I decided to call it a day at that point as it was unlikely to go much higher.

I'm still a little worried about the PSU temperature, but having searched the forums I'm not the only one at least. I'd love to know the recommended maximum temps for that particular component.

Other than that, no problems, no glitches, further confirmation that I was jumping to conclusions when that mild flicker bug appeared a few days ago.

I'll still be more comfortable running smc at the slightly higher levels I think, I doubt any damage is being done but if it gives one of the components an extra year of life it'll be worth it :)
 
Warenty???

Does smcfancontrol void apple's warranty?????
Does Temperature Monitor void apples warranty.

I don't want to lose lot's of money I just spent on a 3 year warranty...

:apple: I'd like to be able to use this because my iMac overheats when used or left on for long periods of time :( but don't want to lose a couple hundred spent on a 3 year warranty from apple. :apple:


What I mean't is I was worrying about The top heating up alot...
 
jam7967 said:
Does smcfancontrol void apple's warranty?????
Does Temperature Monitor void apples warranty.

I don't want to lose lot's of money I just spent on a 3 year warranty...

:apple: I'd like to be able to use this because my iMac overheats when used or left on for long periods of time :( but don't want to lose a couple hundred spent on a 3 year warranty from apple. :apple:
Click to expand...

I doubt that either will void your warranty. That said, if the machine is overheating it sounds to me like you're either using it someplace too hot or there is something wrong with it and instead of jacking up the fan speeds you should be sending it back to Apple for service or replacement.
 
This comment doesn't completely apply to this thread, but I think it's of note: We have two 24" inchers in our family. One 2.4 and an "Extreme 2.8"... which runs very noticeably hotter - simply by touching the top of the aluminum case, where the standard 2.4 stays warm, but doesn't get nearly as hot.
 
Can't help or comment much on using games on the new iMacs.

I took of all the fan/temp monitoring stuff, caused more problems than they are worth -- and until there is a problem with the machine, I didn't like the software hassles.

Basically they interacted with some other software to futz a couple system settings every now and then.

--

I have zapped it on the top a couple times with a laser temp probe and saw 108°F on the top after using heavy graphics apps.

So it wasn't as hot as it felt.
 
brasscat said:
This comment doesn't completely apply to this thread, but I think it's of note: We have two 24" inchers in our family. One 2.4 and an "Extreme 2.8"... which runs very noticeably hotter - simply by touching the top of the aluminum case, where the standard 2.4 stays warm, but doesn't get nearly as hot.
Click to expand...

do you play games on the 2.4 and 2.8?
 
My 2.4 becomes extremely hot too. 10 minutes of Crysis and the top left is too hot to touch for even a second.

It doesn't bother me though - it never misses a beat.
 
update

So it's been a while since I first saw this thread, and I have been using smcFanControl and iStat ever since and have been reasonably happy. The other day I forgot to up the speeds before I started playing a graphics intensive game, after a while I started getting weird screen problems. Sure enough, my temps were through the roof. (Wish I had a screenshot.)

Conclusion, without fan speed controlling software, my iMac would be toast. I'm considering taking it in to Apple. By the way, with no fan control, my fans never ramp up on their own.
 
Really? I push mine really hard in Windows games and it has no problems at all.

The other day I forgot to up the speeds before I started playing a graphics intensive game, after a while I started getting weird screen problems. Sure enough, my temps were through the roof. (Wish I had a screenshot.)

Conclusion, without fan speed controlling software, my iMac would be toast. I'm considering taking it in to Apple.
Click to expand...

Ok, so back everything up and try to destroy it by uninstalling SMC and running your graphics intensive game on a timedemo loop.

Let us know how you get on.
 
durija said:
So it's been a while since I first saw this thread, and I have been using smcFanControl and iStat ever since and have been reasonably happy. The other day I forgot to up the speeds before I started playing a graphics intensive game, after a while I started getting weird screen problems. Sure enough, my temps were through the roof. (Wish I had a screenshot.)

Conclusion, without fan speed controlling software, my iMac would be toast. I'm considering taking it in to Apple. By the way, with no fan control, my fans never ramp up on their own.
Click to expand...

So if i use smc fancontrol in Mac OS and then switch to Windows, do the fancontrol settings automatically transfer when using windows or do they go back to Mac's default settings?
 
If you select restart and hit option key, yes. If you shut down, no, it goes back to default speeds.
This comes on handy when I want to play COD4 and set the speeds to 3000rpm. But even after 3 hours or so of gaming in the summer, the top left corner can fry an egg. I just don't believe in the normal fan ramp up of the imacs. Never saw fan speeds go past 1700rpm under heavy gaming/movie exporting in osx. Cpu throttles like in my macbook past 80ºc, the power supply reaches 82º and the hdd near 65ºc (very dangerous zone imho)
 
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