Thermal Conductance 101 with Dr. Fylladitakis

Simplified, thermal conductance is the ability of a material or arrangement to conduct heat. Thermal conductance is inversely related to the absolute thermal resistance, meaning that a lower absolute thermal resistance will improve thermal conductance. In our particular case study, that arrangement is the CPU/Cooler setup. When studying arrangements, the absolute thermal resistance of the entire arrangement is the sum of the thermal resistance that each individual part has. Anything that lowers the absolute thermal resistance of the CPU/Cooler arrangement will result to better thermal conductance, i.e. lower operating temperatures. Vice versa, if the absolute thermal resistance of the arrangement increases, the thermal conductance will be lowered.

The figure above displays a simplified CPU/Cooler arrangement. At the bottom layer we have our CPU die(s), the middle layer is the CPU’s copper lid and, finally, the top layer is the CPU cooler. With such a setup, we have three individual thermal resistances: R1) the CPU’s die (heat conduction from the CPU die to the CPU lid), R2) the CPU’s lid (heat conduction from the CPU’s lid to the cooler), and R3) the cooler’s absolute thermal resistance. These three resistances sum up to make the total absolute thermal resistance of the CPU/Cooler arrangement. Simplified and assuming one-dimensional conduction, each absolute thermal resistance depends on three things: a) the length of the material in parallel to the heat flow (i.e. its thickness), b) the thermal conductivity of the material, and c) the cross-sectional contact area.

The cooler’s absolute thermal resistance obviously depends on the cooler itself (size, materials, design, air flow, etc.). However, no matter how good a cooler is, the absolute thermal resistance of the entire arrangement can still be poor if any other thermal resistance is too high. For example, it is known amongst enthusiasts that some of Intel’s previous processor generations had poor thermal performance that was unjustified given their very low power requirements. That was because the CPU’s lid was making poor contact with the CPU’s die(s), greatly decreasing the thermal flow between the die and the lid. Hardcore enthusiasts were “delidding” their processors in order to fix this issue.

Introduction AMD Threadripper Processors & Cooler Compatibility
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  • iter - Friday, March 16, 2018 - link

    Oh you are sorry for me, are you? Well that sure makes you better LOL. My life rocks because there are no spineless, fake people in it. Being a true human is a deterrent for folk like you, and that is a great thing I wouldn't change for the world, as people like you are mediocre, utterly boring and of no value whatsoever, and only fit in one place - circle jerks of similar individuals. So better save your sorry for your own sorry self. Now go find another mindless drone like you to pat eachother on the backs to create the illusion of self-worth you so desperately need. Maybe talk about gender self-identification and whatnot... Reply
  • Jedi2155 - Friday, March 16, 2018 - link

    While you my have no fake people in your life I'm going to go out on a limb and say your circle of trusted individuals is quite small. It seems you may be limiting yourself on what you're willing to understand and respect on the basis of feeling superior to others. Reply
  • bobcov - Friday, April 6, 2018 - link

    LostWander has a point which you have quite strongly validated through the wording of your post. His advice has merit. Reply
  • Arbie - Saturday, March 17, 2018 - link

    Iter, did you forget your WccfTech password? That's the right place to warp general commentary into a personal attack chain. Reply
  • linuxgeex - Monday, March 19, 2018 - link

    Agree. It's obvious to anyone that a CPU cooler only works when it's attached to the CPU. A cooler that is attached only to a portion of the CPU is intuitively only cooling the portion it is attached to.

    The article could have just said that. Instead they went so deep-dive on it that honestly it felt patronizing, and that's why I agree with your response. This article is completely over-written, one might even go so far as to characterize it as self-satisfied smart-ass rant... and don't get me wrong on that... some people actually enjoy participating in reading someone else's self-glorification, and have such small egos that they don't mind their time being wasted in the process, lol.

    As for the "hate" LostWander is speaking of, that was in s/he/it's own mind. LostWander accuses you of hate only because they don't hear the sarcasm you are directing at the Engineers who suggested building and marketing the adapter which this article reveals to be so ineffective. Those individuals deserve your wry comments because they were fully aware of the shizzle they were encouraging consumers to purchase.

    Instead, Lostwander is so defensive that s/he/it assumed that any negativity must be directed toward themself personally and so they jumped in to defend their ego by attacking you, and that is sad, especially given they believe they were delivering a message of acceptance.
    Reply
  • eek2121 - Thursday, March 22, 2018 - link

    I wouldn't say that. Prime95 small-ffts load gives me 45.5C on my Enermax TR4 AIO. That's more than 'marginal'. Furthermore, if you overclock to 4.1 GHz, it is likely you'll find the Noctua unable to keep the CPU temp below 68C. My Enermax has no problems doing so. Reply
  • romrunning - Wednesday, March 14, 2018 - link

    "AMD’s Threadripper processors certainly do not require liquid coolers to function properly at stock"

    Can we add the performance of a liquid cooler to the charts to see how the air TR-4 cooler performs against it?
    Reply
  • eek2121 - Thursday, March 22, 2018 - link

    I can tell you significantly better then that noctua. Reply
  • mrpiggy - Wednesday, March 14, 2018 - link

    'Cus it's all about that base, 'bout that base, no treble.. Reply
  • SaolDan - Wednesday, March 14, 2018 - link

    Chuckle Reply

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