Ever since their launch last year, AMD’s Threadripper CPUs have been the center of many discussions and debates. Due to their unique design – both physically and architecturally – cooling requirements and efficiency are some of the major discussion topics. All of the Threadripper models have significant power and cooling requirements, with AMD recommending liquid cooling right off the bat. However, the actual thermal design power (TDP) specifications are not that high, suggesting that a good air-based cooler could easily cope with the thermal load. And here is where things are getting complicated.

Threadripper processors step quite far outside typical CPU designs in several ways, one of which is their relatively massive physical size. The CPU’s surface area is much greater than that of all consumer CPUs before them, including Intel's LGA 20xx sockets. This sizable design choice is not because AMD couldn't squeeze the CPU dies physically closer, but because Threadripper's size is the minimum size that their engineers calculated to be effective for both the mechanical strength of the package and for sufficient heat dissipation. When Threadripper was announced, nearly all cooler manufacturers rushed to provide adapters for their products to be mounted on Threadripper processors. AMD themselves include an adapter for Asetek-based liquid coolers inside the package of the Threadripper processors. User experiences with such adapters, including our own, were less that ideal. So today we're going to take a look at why AMD's thermal requirements are so exaggerated and showcase why adapters are not effective.

AMD Threadripper Coolers: Almost the Same, But Not Quite

Most available coolers were designed with the previous generation processors in mind, and their contact surface is significantly smaller than the CPU’s surface area. Many manufacturers rushed to offer adapters for their products to be mounted on Threadripper (socket TR4) processors and several posted/presented simple mods that convert AM4-compatible coolers to fit as well. Using socket adapters and mounting typical coolers on Threadripper processor does work, but they are only partially covering the CPU’s surface area. 

Left - Noctua NH-U14S with AM4-UxS mounting braces, Right - Noctua NH-U14S TR4-SP3

There have been many debates whether the same exact cooler but with a proper contact surface would have better thermal conductance. According to basic thermal engineering theory, the cooler whose base covers more of a processor's lid should perform better. In the following pages we examine the theoretical aspect of this supposition and follow up with an experimental case study.

Thermal Conductance 101


View All Comments

  • FireSnake - Wednesday, March 14, 2018 - link

    Awesome review, thank you! Reply
  • iter - Wednesday, March 14, 2018 - link

    Hmm, the cooler should cover the chip it is cooling... who would have thought that to be the case?

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

    Moot point, as nigh end noctua coolers easily beat AIO water coolers and can only be marginally bested by significant custom loop systems.

    Finally, it might have been a good idea for amd to invest in a third socket for dual die chips. Sure they saved some money on underusing SP3 for TR, but that might have backfired more than the savings - the socket is huge, complex and expessive, takes up too much space, limits mobo designs and a lot of users report serious problems with the installation. On top of rendering existing coolers rather inefficient, something that would not have been a problem with a dual die socket.
  • ravyne - Wednesday, March 14, 2018 - link

    I wager we might see AMD introduce a new socket with Threadripper being a success. It's been reported that TR was essentially a passion-project for the engineers and so they didn't have the full resources at their disposal, even if they had the blessing of execs. There's the Epyc embedded 3000 series just coming out, which is a 1-or-2-die package supporting full PCIe lane potential and quad-channel memory in the two-die configuration, but it's designed to be soldered. Perhaps we'll see a socketed version, which would make ITX form factors possible and uATX more comfortable, and possibly reduce motherboard socket costs. I think they've committed to supporting the current TR socket for 3 generations of CPUs, but supporting two different sockets shouldn't be overly difficult given the multi-die/interposer construction and being able to leverage similarities/economies-of-scale with Epic 7000. Plus, if mainstream core counts continue to increase we're gonna need more PCIe and DRAM channels anyway, so maybe this just becomes the new mainstream socket. Reply
  • eek2121 - Wednesday, March 21, 2018 - link

    We won't see a new socket for a while. Threadripper was a HUGE success and AMD wants to keep the Gravy Train rolling. I bought an Enermax 360 for mine and even when overclocked to 4.1 the machine runs silent and cool. Reply
  • Alexvrb - Wednesday, March 14, 2018 - link

    Not sure how you could have "serious problems" with the install. I for one like the overbuilt socket. I mean, unless you're one of the strange people aiming for an ITX TR build.

    I don't have any plans to own a TR system for personal use... I don't need more than 8 cores, quad channel RAM, or a crapload of PCIe lanes. But if you do it's a decent platform, and relatively affordable.
  • eek2121 - Wednesday, March 21, 2018 - link

    I would love to see them make a mobile variant. Reply
  • LostWander - Thursday, March 15, 2018 - link

    No need for the hate. It's an obvious conclusion but it's nice to have some of the "why" laid out so well for those of us with only introductory engineering knowledge. Reply
  • iter - Thursday, March 15, 2018 - link

    I wasn't aware that it takes engineering knowledge, introductory or otherwise, to possess common sense. "Contact" IMO is a pretty intuitive and self-explanatory concept...

    Yet it seems certain overly sensitive individuals have put emphasis on developing nonsensical sensibilities and neglected developing precious common sense... To the point of misidentifying sarcasm as "hate"... It is not hate, it is simply not being a dumb robot person whose worldview is so narrow that literally techniques slip outside of his norms for "appropriate"...

    I for one don't find it all that positive that people need such things explained in the first place, it is rather alarming to say the least.
  • LostWander - Thursday, March 15, 2018 - link

    Lots of assumptions there friend. Really sad honestly there were a lot of better (and more accurate) interpretations of my comment available.

    I'm so sorry for anyone in your life. Get help for their sake.
  • 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

Log in

Don't have an account? Sign up now