Which CPU is the coolest at full load intensive tasks?

Discussion in 'iMac' started by Moriske, Nov 2, 2015.

  1. Moriske, Nov 2, 2015
    Last edited: Nov 2, 2015

    Moriske macrumors member

    Joined:
    Oct 19, 2015
    #1
    Following this post I would like to know if the i5 is cooler and quieter compared to the i7?

    iMac 27" 5K
    i5 3.3GHz (6600K)
    or
    i7 4.0GHZ. (6700K)
     
  2. Sirmausalot macrumors 6502a

    Sirmausalot

    Joined:
    Sep 1, 2007
    #2
    They are both 65watt chips made on the same manufacturing technology. Both are properly cool and quiet except when you put them under load (video encoding etc). Then they get properly hot and the fans speed up properly (and are audible). Assume the apple engineers did a proper job and get the best chip for your uses. If you are encoding video or using other processor intensive apps, get the i7. Otherwise the i5.

    Edit, as someone else pointed out, the i7 will finish the task faster, thus ultimately cool down faster and the fans will quiet down as well.
     
  3. Maxx Power macrumors 6502a

    Maxx Power

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    Apr 29, 2003
    #3
    They are both 91 Watt chips according to Intel's webpages. Preliminary reviews of both (say at Anandtech) indicates that the i5 is the cooler chip by quite a bit (lower actual TDP).
     
  4. Moriske thread starter macrumors member

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    Oct 19, 2015
    #4
    I encode videos and also make use of intensive CPU tasks.
    But really i can not get used to the noise from the fans.

    Even both processors i5 vs i7 has the same max 91W TDP, I wonder whether the i5 without Hyper-Threading runs cooler compared to the i7?
    I prefer a quiet system, than a system that is a little bit faster.
     
  5. Sirmausalot macrumors 6502a

    Sirmausalot

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    Sep 1, 2007
    #5
    Your best bet is to get a liquid cooled PC then.
    But I doubled checked and yes, they are 91W chips as Maxx said. Again, you will hear the fans when using the CPU and the i7 will finish the task faster. Pretty much as soon as you start pushing the cpu, the fans will ramp up. But I think a pair of noise cancelling headphones are what you really need http://www.cnet.com/topics/headphones/best-headphones/noise-canceling/
     
  6. Moriske thread starter macrumors member

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    Oct 19, 2015
    #6
    Not really a solution :)

    As a reference
    My Mac Mini 2.3GHz i7 is quieter under full CPU load!!
     
  7. Maxx Power macrumors 6502a

    Maxx Power

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    Apr 29, 2003
    #7
    Unfortunately, Apple is obsessed with form factors lately. It sounds like either an iMac or a MacPro would be your Mac-based solutions. However, neither is known for being whisper quiet under load.

    As for the actual differential between the two CPUs, see this: http://www.tomshardware.com/reviews/skylake-intel-core-i7-6700k-core-i5-6600k,4252-11.html

    There is about a 25W higher power draw for the 6700K as tested compared to the 6600K.

    Scroll down to see the summary table and the graph on the core temperatures during testing (same heatsink used for both CPUs). It seems the i5 is quite a bit cooler (~20 degrees C).
     
  8. Moriske thread starter macrumors member

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    Oct 19, 2015
    #8
    I have an iMac i7 + M395 and want to compare it with a 3.3GHz i5 (6600 without the K)
    i5 (6600 - TDP 65watt) vs i7 (6007k - TDP 95watt)

    My iMac fan speed is/remains at maximum fullSpeed, CPU at +/- 95°C
    Would like to see a picture of the i5 iMac under full load as compared to the i7 iMac.
     
  9. iemcj macrumors 6502

    iemcj

    Joined:
    Oct 31, 2015
    #9
    I've always been curious about the people that have a problem with the fan making noise. Are you hanging out in a dead silent house or something? Who does that? At all times I either have music going, a podcast, or I'm streaming a tv show. It just seems so weird to me to sit there in total silence then get upset when a soft fan sound starts to keep your computer cool as you push it to the max with a very cpu intensive task.

    Not belittling you completely OP but just trying to understand this oddly specific situation you're in.
     
  10. Moriske thread starter macrumors member

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    Oct 19, 2015
    #10
    Not belittling you completely OP but just trying to understand this oddly specific situation you're in.[/QUOTE]

    No discussions, just want facts, see pictures and compare it from iStat :)

    This is my iMac i7 + M395
    [​IMG]

    [​IMG]
     
  11. Sirmausalot macrumors 6502a

    Sirmausalot

    Joined:
    Sep 1, 2007
    #11
    I agree. You put a computer under load by compressing videos and the fan ramps up. That is what it is supposed to do and people will likely find that there is no solution that will make them happy. Movies can be downloaded from iTunes or Amazon or if you already own the DVD, a sound legal argument can be made that you have purchased a license and you can get a digitally encoded copy from 'elsewhere'. Therefore no stress on the CPU and no noise.

    You can't drive a car and not expect the engine to get hot and for it to make road noise. Furthermore, the OP is using charts and graphs that actually don't show a problem. If there is a real issue with the computer, it would be worthwhile to ask some questions. but from what you've told us, the computer is actually functioning properly.
     
  12. iemcj macrumors 6502

    iemcj

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    Oct 31, 2015
    #12
    Moriske, the van is the exact same in both units. If both the i5 and i7 are at full tax, then yes the i7 will be warmer. It's at a faster clock speed and able to multithread so it's going to be able to get the same task done quicker.

    You have two options. Get the i7, get a processor that was more purpose built to handle high draw tasks like this, it'll likely get warmer (though I have yet to see proof of this on two identical tasks), and it'll get done faster so your "annoying" fan will stop sooner.

    Get the i5, get something not as powerful, it'll end up having to work at max power on a task that the i7 could do at 70% draw, it'll take longer to get done, your fans MIGHT not need to run as fast, but itll for sure be running longer.

    Honestly as others have told you, you're basically asking your computer to work really hard. The i7 can do this work better and faster, the i5 can't. So over time it makes more sense to have the i7 because it's built for this purpose, you're straining the i5 harder for the same task. It's like buying a v6 truck and a v8 truck and being in shock that the v8 is hotter when it revs up. Of course it is, that means it's doing it's job. It'll be done and cooling down while the i5 little v6 truck is still at max rev trying to keep up.
     
  13. Moriske thread starter macrumors member

    Joined:
    Oct 19, 2015
    #13
    Support Apple tells me that this would be wrong and suggested himself for an exchange.
    Weird?

    When I convert an entire audio folder (lossless to MP3), I also have 100% CPU and 100% Fan speed, noise.
    Fan is at full power 100% ....... CPU +/- 96C, no breathing space left?

    ****Want someone to convince me, post pictures of a same configuration****
     
  14. joema2 macrumors 65816

    joema2

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    Sep 3, 2013
    #14


    That is a good point. I built a Windows PC which has many different Noctua fans in it, all turning at a fairly slow RPM. It is pretty quiet but when stressed the GPU fan speeds up. That is common. I agree you can build or buy a special PC that maintains a constant acoustic output no matter what the CPU/GPU load but that is not a typical or normal configuration. They are usually way louder than an iMac in normal use. I'd be interested which computers are quieter than an iMac when running Intel Burn Test and Furmark simultaneously.
     
  15. Maxx Power macrumors 6502a

    Maxx Power

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    Apr 29, 2003
    #15
    I think there is at least one really long thread on here about the new iMacs and how they get hot/loud under various loads.

    Based on the internal design of the last few generations of iMacs (thanks to iFixit), I would have to conclude that there isn't any other alternative than to ramp up the fans to cool these chips. I am very familiar with PC-building and can tell you that a larger heatsink requires less fan speed and larger fans, both of which contributes to quietness. Apple's heatsinks are generally speaking, small for the TDP of the chips that are to be cooled.

    If Apple insists on cramming powerful hardware into their skinny iMacs, I think you need to be prepared for a louder and hotter machine, if this trend continues and of course, assuming no major advances in cooling (like using the backside of the iMac as a passive heatsink, in addition to the fan).
     
  16. joema2 macrumors 65816

    joema2

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    Sep 3, 2013
    #16
    I have a 2015 iMac 27 and it is very quiet. My impression is it's quieter than the 2013 iMac 27 that sits beside it on my desk running the same software. At high load it is quieter than my Windows PC at similar loads.

    Many personal computers ramp up fan speed when under heavy load. How many PCs don't do that?

    The PC I built has a Noctua NH-D14 CPU cooler, Noctua case fan and two Cooler Master 200mm fans turning at 400 rpm. It is relatively quiet for a PC but it's way louder than my Imac 27 both at idle and full load.
     
  17. Maxx Power, Nov 5, 2015
    Last edited: Nov 5, 2015

    Maxx Power macrumors 6502a

    Maxx Power

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    Apr 29, 2003
    #17

    Many PCs don't ramp up at all. When you build your own computer, you can set the BIOS/UEFI fan settings to be at a constant rate, or respond to temperature changes, or use a dedicated fan controller. People who also do liquid cooling (all-in-ones, or otherwise) do not usually ramp the fans. If you have an over-cooled computer, your max load temperatures on low fan speeds are already low, there is no point to ramp up based on temperature. Many people build their computer this way, given it is an option available to them.

    Your PC is louder mainly because you have quite a few fans and a leaky case. Some quiet-performance PC builds uses only 1 exhaust without a CPU fan (passive heatsink aided by the exhaust) and 1 PSU fan. Those are dead silent. Again, if you purchase one of those "gamer" cases with fans attached to nearly every side, it will be noticeable in noise no matter what you do, simply because any noise made by the fans will leak directly out to the user without damping. There is a whole market for PC builders who want some extra quietness (see SPCR's excellent website dedicated to this). Turning down the fans doesn't always guarantee lower noise either, as bearing noise (gurgle or chug) becomes more pronounced.

    I don't have a shiny new iMac and I never did say anything directly about its noise qualities. There are plenty of available posts around here for those who are interested. At any rate, human loudness perceptions are closer to measurements in Sones than it is in Decibels, so you may be sensing a spectrum-quality of the noise rather than the power of it.
     
  18. joema2 macrumors 65816

    joema2

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    Sep 3, 2013
    #18


    That is my point. Yes you can build a specialized quiet PC with constant speed fans, but I don't think that is typical of most manufactured PCs. The Dell XPS 27 which has a thicker case than the iMac and more opportunities for cooling was described by Anandtech as "brutally" loud. The big thick case and 60% more weight did not help them much.

    The iMac is a mass manufactured computer so it's only fair to compare that to other mass manufactured computers in a roughly similar price/performance range. The fact you can make a faster custom built overclocked PC using liquid cooling or a quieter custom-built computer is not really relevant. Most potential iMac customers don't want to build their own machine or even have someone else do it for them.

    It would be interesting to do an acoustic noise test on a typical workstation-class PC like a Dell XPS 8900 -- which Dell markets to "creative professionals" -- run Intel Burn Test and Furmark simultaneously and see if the fan ramps up and what the noise level is vs a 2015 iMac.
     
  19. richwoodrocket macrumors 68020

    richwoodrocket

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    Apr 7, 2014
    Location:
    Hamburg, NY
    #19
    I think the OP is just looking for things to complain about.
    There's an easy solution to this problem, as others have suggested. Listen to some music or something to drown out the fans.
     
  20. Moriske thread starter macrumors member

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    Oct 19, 2015
    #20
    Do You Really Think Thiso_O
    I have reason enough to want to enjoy my € 3.000 iMac.

    Next week comes the new "iMac i7."
    Very curious whether the cooling of the CPU at full load is now better able to control?
    If so, I have the ability to Fanspeed and noise to scale back slightly. Excluding the effect of CPU throttling.
     
  21. matreya macrumors 65816

    matreya

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    Nov 14, 2009
    #21
    I love how you start a new thread just because you don't like all the advice people gave you in the first one. When your new iMac arrives and you push it to 100% CPU on ALL CORES, the fan will get loud. Deal with it.
     
  22. Buerkletucson macrumors 6502

    Buerkletucson

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    Sep 12, 2015
    #22

    x2
     
  23. Maxx Power macrumors 6502a

    Maxx Power

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    Apr 29, 2003
    #23
    I definitely think the iMac is better built than any other all-in-one out there. That's for sure. I think I am comparing by function (family desktop to family desktop) whereas you are comparing by form factor (all-in-one to all-in-one).

    As a consumer (and not workstation, for example) level gear, the iMac, as well as the Macbooks are generally quieter than many other equivalents. Having said that, I am sure Apple can build these quieter if they wanted to, because even I can spot a few things they may be able to try.
     
  24. iemcj macrumors 6502

    iemcj

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    Oct 31, 2015
  25. cynics macrumors G3

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    Jan 8, 2012
    #25
    And if you work load is based around audio recording then what?

    Granted I'm playing devils advocate because my iMac from 2013 is incapable of raising the fan past 1400 RPM with its CPU and GPU (i5 3.4ghz and 775m) running at 100%.

    http://forums.macrumors.com/threads/my-imac-i7-runs-too-hot.1934430/page-2#post-22193890

    Regardless I don't feel someone wanting the quietest iMac available should be considered complaining, nor should they need to use a time machine to acquire one.
     

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