Cooling iMac Down?

Discussion in 'iMac' started by nylock10, Feb 16, 2008.

  1. nylock10 macrumors regular

    Jun 26, 2006

    My iMac has started to run pretty hot lately (HD runs hot, idles at around 50 degrees celsius), also the GPU diode has been around 55 - 60 degrees celsius when idle.

    I also hear the fans constantly, so I looked at the vents on the back of the computer and I noticed that there's a ton of dust in the back. I'm assuming this must be a problem with improper air-ventilation.

    But what do you guys think, should I take it to Apple and see if they will clean it some how?

    Also, what do you guys recommend I do to help keep it cool for the time being?
  2. Ugg macrumors 68000


    Apr 7, 2003
    Have you had it long?

    The best thing to do is to take a vacuum and clean the airvents. DO NOT use a can of compressed air, that will only blow the dust into the machine and make things worse.

    I'd call your Apple store and ask them if they have any specific recommendations.
  3. Muncher macrumors 65816


    Apr 19, 2007
    Don't use a vacuum! Blow air through the speakers, it is more efficient. Use smcfancontrol to set the fans fairly high, and blow air through the speakers. This should get rid of most of your dust. Keep in mind that your imacs' air intakes are the speakers. If your desk is really dusty, so will your imac.
  4. Smoogz macrumors member

    Feb 13, 2008
    Lafayette, LA
    yes exactly what these 2 guys said. Either try and remove the dust yourself or bring it to the Apple store for cleaning advice. Whatever it is you do make sure you keep the computer and the area around it dust free. Out here everyone is having the same problems but we're in the desert. Good Luck ;)
  5. nylock10 thread starter macrumors regular

    Jun 26, 2006
    Okay, I'll look into those two things!

    The previous room the iMac was in was really dusty, the new one is very clean.

    That must have been what the problem was, I had an old Dell in the same place the iMac used to be and it looked like the inside of a vacuum bag.

    So, turn the fans up a little with SMCFanControl and use a can of compressed air to "blast" the dust out?

    Does that force the dust to become loose, then the fans do the rest of the job sucking it out of there and out the back port or something?
  6. star555 macrumors regular

    Feb 17, 2008
    Cambodia - Thailand
    Have I got this right..?, the cooling air going into an iMac is drawn up into
    the bottom speakers, it then passes through the speakers and is drawn into the internal cooling fans, and blown out.? Where is the ''warm air '' blown out to ..?

  7. Siriosys macrumors regular


    Dec 24, 2007
    New Zealand

    You are correct. As for the vent - this is located at the top of your iMac and while sitting at your iMac if you put your left hand up and touch the top of you machine, it'll feel quite warm. About 1 inch down from the top of the computer at the back is the air vent. Using SMCfanControl, turn your fans up to half way and then wait a couple of minutes. Eventually, you'll feel warm air coming out the top of your machine.

    The placement of the vents makes complete sent. Hot air rises so it's most efficient to have the vents at the top of the machine.

  8. star555 macrumors regular

    Feb 17, 2008
    Cambodia - Thailand
    Thank you Siriosys for your reply, now I know how the air is vented it makes more sense.

    Thanks star:)
  9. jimmerz macrumors newbie


    Feb 24, 2010
    amsterdam ny
    i have a brand new imac 27inch, i7, 8 gig of ram and 2 tb of drive space with the ati graphics processor in it.. my box runs hot if its on for a while and im doing stuff. if i just let it sit she cools down real quick. im using a gadget sensor reader that tells me the cpu heat sink temp and can also do ambient temp as well as gpu and some other stuff like memory etc.. my question is if apples web site says "Operating temperature: 50° to 95° F (10° to 35° C)" so does that mean the computer can function in a room at those temps or is it the operating temp of the machine itself? because it does not say and my machine according to this other app i have installed i called istats. my temps read as follows and all are in Celsius ambient 16, cpu 34 but ive seen it run at higher temps than the operating temp stated above, gpu diode 54, gpu heat sink 50, memory controller 40, cpu fan speed 938.

    i also saw you guys posted something about smcfancontrol, is that installed already or is it a third party app i can install? and where can i find it. im a mac newbie but not new to computers so i pick up on stuff quick. any help would be appreciated.

    Attached Files:

  10. TMRaven macrumors 68020


    Nov 5, 2009
  11. aki macrumors 6502a

    Mar 2, 2004
    smcfancontrol is a third party app, free. google for it. it works well.

    to monitor temperatures you can use istat/istatpro. again google is your friend.

    re using a vacuum, i didn't hear this till recently but apparently there can be a static buildup which can damage components, so a regular plastic vacuum for cleaning is a poor choice

    for quick dust removal just running your finger along the vents/speakers at the base of the imac/monitor can remove some, if its bad

    as far as what temperatures are safe is concerned, more or less in the imac the most vulnerable part is the HD lifespan. People seem to say temps over 50C arent so great and regularly over 55 for long periods are bad

    good luck
  12. awbunn macrumors newbie

    Mar 3, 2010
    Does anyone have info on what the optimum temps should be? I have a brand new 21.5 " iMac and I've found the top of the case to be really hot especially when playing a game, in this case World of Warcraft. iStatpro showed the GPU at upper 60's even hitting 70 once and the HDD at 53. Using smcfancontrol brought the temps back down but Im still concerned.
  13. MacHamster68 macrumors 68040


    Sep 17, 2009
    Gaming will bring these results on any computer/pc , why you think people invest in better cooling fans ,more efficient heatsinks or even water cooling , when they play games on computers /pc's ,or if they are extremely serious about gaming even in liquid nitro cooling systems , most do that on their gaming rigs for a reason :cool: reason is to bring temps down while playing games , but these are no options for you, as it would need some serious case modding , so your only option is to get your fans spinning faster to cool things down or
    just lower your graphic settings in the game, the imac can play games, but it is not a gaming rig , so don't expect it to behave like one.
    Gaming is the most demanding task for cpu and gpu and hdd ,they will get hot then , its a simple fact
  14. Wrathwitch macrumors 65816

    Dec 4, 2009

    I know this might sound stupid but if you have space in the back you can place a small fan also. I run World of Warcraft sometimes for like 8 hours + and I know from my experience with laptops the value of an external cooling source. Computers like cool.

    The fan does two things, first it cools the aluminum which helps act as the heat dispersal, and secondly it adds to the air flow that runs from the bottom up through the top. It also as a perk prevents dust from gathering at the bottom (within reason) due to the air circulation of the fan.

    Because the screen is so bloody huge, I don't even see the fan and it is quiet. The result is the machine stays as cool as if I was just running it to check emails etc. I will have to look into the fan control thing, but again, why put the burden on the machine especially when choosing to run a program that the machine really isn't primarily designed to do (esp for extended periods of time).
  15. TMRaven macrumors 68020


    Nov 5, 2009
    Could you post the mean temperatures of the gpu/cpu and hdd with and without the fan in the back?
  16. Wrathwitch macrumors 65816

    Dec 4, 2009

    I will look into it. Right now I am workin mids so I will try to do so on my days off. I will need some means of measuring or finding out what the temperatures are. Since I am a Mac Noob could anyone point me to the software?
  17. mrsir2009 macrumors 604


    Sep 17, 2009
    Melbourne, Australia
    Try clean out the dust in the vents with a vac cleaner. Also, download SMC Fan Control help cool it down:cool:
  18. TMRaven macrumors 68020


    Nov 5, 2009
    iStat Pro or iStat menus will keep an eye on your temperatures and fan speeds.
  19. Wrathwitch macrumors 65816

    Dec 4, 2009
    OK I got around to some temperature fiddling. Note that when I say fan I mean the one I have BEHIND my computer. On lowest setting.

    Heres my basic start up stats:
    Ambient temp: 14 deg C
    CPU A Heat sink: 25 deg C
    Graphics Processor Heat sink: 35 deg C
    Memory Controller: 26 deg C
    optical drive: 22 deg C
    Power Supply Position 2: 28 deg C
    Smart Disk: 21 deg C
    Core(s) 1-8: between 22 - 24 deg C

    Here is me surfing with no fan(behind) (some bit torrents)

    Ambient temp: 18deg C
    CPU A Heat sink: 46 deg C
    Graphics Processor Heat sink: 48 deg C
    Memory Controller: 38 deg C
    optical drive: 32 deg C
    Power Supply Position 2: 45 deg C
    Smart Disk: 35 deg C
    Core(s) 1-8: between 32 - 33 deg C

    Gaming under normal game load for about an hour (no fan in back)

    Ambient temp: 25 deg C
    CPU A Heat sink: 56 deg C
    Graphics Processor Heat sink: 78 deg C
    Memory Controller: 77 deg C
    optical drive: 47 deg C
    Power Supply Position 2: 71 deg C
    Smart Disk: 51 deg C
    Core(s) 1-8: between 57 - 60 deg C

    Gaming under Heavy graphics load for 2+hours (with fan on low setting in back):

    Ambient temp: 24 deg C
    CPU A Heat sink: 56 deg C
    Graphics Processor Heat sink: 76 deg C
    Memory Controller: 52 deg C
    optical drive: 43 deg C
    Power Supply Position 2: 68 deg C
    Smart Disk: 45 deg C
    Core(s) 1-8: between 58 - 66 deg C

    On average it seems I save aprx 5-6 deg temperature between having the fan in the back and not. I am not sure how the savings would add over time but I suspect that any amount of extra cooling when under load has to save the machine over time.

    I didn't run it under heavy raiding load for a couple of hours in the test because I figure based on the existing stats, that it would still add up to about 6-8 degrees cooler with the fan.

  20. chkdg8 macrumors 6502

    Oct 24, 2007
    As previously mentioned, gaming does indeed bring up the temperatures system wide. Ever since Steam rolled out several weeks ago, I've noticed that playing for over an hour on my mac is risking it. I have iStat Pro to display it in Fahrenheit for me but I'll post pics in Celsius as well.

    Celsius (left) Fahrenheit (right)

    Attached Files:

  21. 3rd Doctor macrumors member

    Dec 4, 2009
    Risking what exactly?

    At those temperatures nothing is going to fry if that's what you are worried about.
  22. Stealthipad macrumors 68040


    Apr 30, 2010
    The price we pay for the iMac look is poor ventilation and increased heat. The hard drive takes the heat on the chin and there is little doubt the heat will shorten the hard drive's life.

    I would give up a little of "the iMac looks" for an additional vent or two in the back with an extra fan.
  23. TMRaven macrumors 68020


    Nov 5, 2009
    Hm. Seems like there's little incentive to get a fan for the back then. Ramping up the optical drive fan to 3,000+ rpm assures the gpu never goes above 60c while gaming.
  24. jlorre macrumors newbie

    Aug 20, 2010
    adding a few venting holes to the chassis

    hi, i found a good solution to keep my iMac 24" 2008 cool:
    make a minor modification to the chassis:
    1. open the mac (iFixit has clear instructions on how to do disassemble the iMac, e.g.

    1. cut away the upper plastic rim of the venting strip on the back of your iMac.
    You can do this cleanly from the outside of the chassis by letting a 2 mm drill glide on the metal grille, and slowly letting the dril cut away a line in the plastic.
    2. strip away the aluminium adhesive strip that blocks the large rectangular openings in the upper exhaust grille (peel the inox-contact pads off the strip and put them back on the metal grille)
    3. drill a lot of venting holes in the plastic back. You can do this cleanly by letting your drill guide by the holes in the metal upper grille. Drill from the inside of the chassis to the outside. Drill 3 rows of holes this way where you can reach through the grille. Especially the region above the powersupply should be well vented. This is where most of the heat is generated in my case.
    You can see my result in attached picture here, and I am most pleased with it.
    With what I know now I would now make three rows of holes instead of two.

    Attached Files:

  25. Raima macrumors 6502

    Jan 21, 2010
    That's very ambitious. Do you have any data collected before and after the mod was done in terms of temps?

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