The REAL place where airflow enters.

Discussion in 'iMac' started by bluedoggiant, Feb 13, 2008.

  1. bluedoggiant macrumors 68030

    bluedoggiant

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    #1
    I do not believe that place on top of the power plug does anything, air flows, but not much, put your hands under the iMac, you feel the air coming out of the speaker holes.

    My question is, what is that line on the top of the imac, another place where air flows?
     
  2. MrT8064 macrumors 6502a

    MrT8064

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    UK
    #2
    i am pretty sure that air enters by the speakers, and by the power in... and exits along that strip at the top.

    if you use a program like SMC fan control, and crank up the power to full, you can feel a lot of warm air from the top, and cold air movement at the bottom.
     
  3. Muncher macrumors 65816

    Muncher

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    #3
    Yeah, that sounds about right. I know the air comes out on the top, and the only other holes that make sense for apple to make an air intake are the speakers.
     
  4. Siriosys macrumors regular

    Siriosys

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    New Zealand
    #4
    You're correct. The air inlets are at the bottom. Basic physics at play too - hot air rises so it will escape more efficiantly thru the top vent rather than trying to be 'pushed' out the bottom.

    I did a small experiment with my 24incher and placed a fairly powerful fan beneath the iMac and gave it a blast for 15 minutes which resulted in almost immediate plummeting of HD, PSU, and Ambient Temps.

    Placing the fan at the very top and facing it at the 'vent' along the top made very little difference to those temps.


    ....yeah, I know.....too much time on my hands.....
     
  5. Muncher macrumors 65816

    Muncher

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    #5
    That's helpful. So, instead of cranking up my fans to an annoying volume while I play my games, I could put some quieter fans below my speakers... hmm... I see some money in this... $$ :D
     
  6. bluedoggiant thread starter macrumors 68030

    bluedoggiant

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    #6
    what kind of fans did you use?
     
  7. Siriosys macrumors regular

    Siriosys

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    Dec 24, 2007
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    #7
    I just used a couple of hefty chassis fans so they weren't exactly what I'd call quiet. just propped them up underneath and seemed to get the desired results.

    I don't know enough about the insides of the iMac, but I'm wondering where exactly the 'inlet vents' are located along the speaker grills. I couldn't see myself, but I got lazy and couldn't be bothered sticking my Mac on it's back to find out.

    The alternative might be to stick a couple of fans in reverse onto the back of the iMac so they in theory suck away the heat. Having them up there would also possibly enable you to hide the away more efficiently. One could possibly stick them to the back of the iMac with Velcro, however for them to be efective, you'd need to have them up pretty close to make them efficient.

    ....actually, just had an idea. If you have a spare port on an active USB hub, you could use that as a power supply for them ..... and not to mention a variable speed control too........Hmmm, this has me thinking a bit.:D:D:D




    Cheers
     
  8. bobfredson macrumors newbie

    Joined:
    Oct 28, 2009
    #8
    One step further

    I just went one step further and stuck my air conditioner vent under my imac and managed to get the cpu heatsink temp from 56 down to 21, but perhaps that is too cold. I think most processors have an optimum temperature.

    Despite all that i think ill stick to SMC fan control as at least that way my keyboard & mouse fit on my desk as well as my imac :p.
     
  9. SnoopyII macrumors newbie

    Joined:
    Oct 24, 2009
    #9
    This diagram is for the iMac G5 but I am sure most of the iMac family has somewhat similar airflow routing.

    [​IMG]
     
  10. sammich macrumors 601

    sammich

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    #10
    Maybe you could use those little USB fans?

     
  11. richprice macrumors member

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    Apr 27, 2008
    #11
    Dont give intec any idea's or one of these things will be released in aluminum.
     

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  12. Muncher macrumors 65816

    Muncher

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    #12
    Room temperature (21 C) isn't too cold by any means. There are people who use liquid nitrogen for overclocking.
     
  13. fdelapena macrumors newbie

    Joined:
    Jan 3, 2011
    #13
    iMac Fans

    You can actually get a USB powered fan for the Playstation 3 that connects to an available USB port with an external switch, and with a 3M Doublesided tape you can place it underneath for blowing, or on top for suction of the hot air.
     
  14. MacHamster68, Jan 21, 2011
    Last edited: Jan 21, 2011

    MacHamster68 macrumors 68040

    MacHamster68

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    Sep 17, 2009
    #14
    what about the idea to replace the internal speakers, most of us who want sound use external speakers anyway , so replacing the speakers with 2 fans which then would sit at the perfect place ,would make more sense then some fans underneath

    but a bigger exit slot for the air would help too , as someone pointed it out already , hot air is rising and this tiny slot looks nice , but restricts airflow there is a reason why some other manufacturers of AIO systems have many many openings for hot air to get out/cool air coming in ,
    design is one thing and apple tries to make a compromise to keep a slim clean look at the back which hardly anybody sees once the iMac is on a desk and the rear is facing a wall

    but never mind , this discussion is as old as the first iMac G5, but apple has a idea of a case design and sticks to it, they fitted intels in the iMac G5 case and hey heat wasn't much of a issue any more , so the conclusion for apple was to make the case even slimmer, because less heat means longer liftime of the components , not ideal if you want to sell new computers if the old ones last and do the job, its not in apples interest when the imac last longer then apple care , you are supposed to buy a new one , so they have to find the middle way of long life and still convince you to buy a new one , not a easy task if your old iMac still does happily whatever you throw at it

    i personally would love to see a convection cooled iMac again , just like my iMac G3 , no fans needed running since 10 years no breakdowns , still usable for browsing , emailing , watching dvd's , some photoshop and even playing some old OS9 games , and there is no heat issue , 10 years running is a sign that it was possible to build a iMac that lasts without needing apple care , but not good for profits
    i understand nobody would buy today a crt , ok fit a lcd ,but please a matte one and make the whole iMac then convection cooled, all thats needed would be a case design that makes room for heatsinks that are up to the job ,without having fans to rev up when the computer is in use, positive side effect less components, less aluminium due to ventilation holes and cheaper , which should be in apples interest
     

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