Groups > alt.comp.os.windows-10 > #118301

Re: Has anybody ever stacked two CPU coolers?

From	"Commander Kinsey" <CFKinsey@military.org.jp>
Newsgroups	alt.comp.os.windows-10, alt.computer.workshop
Subject	Re: Has anybody ever stacked two CPU coolers?
Date	2020-07-25 23:47 +0100
Organization	X
Message-ID	<op.0ob1l3d5wdg98l@glass> (permalink)
References	<op.0oboc2f2wdg98l@glass> <rfic0j$78q$1@dont-email.me>

Cross-posted to 2 groups.

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On Sat, 25 Jul 2020 23:33:54 +0100, Paul <nospam@needed.invalid> wrote:

> Commander Kinsey wrote:
>> Has anybody ever stacked two CPU coolers? First one fitted normally,
>> then the second welded on top of it. Theoretically, you have twice the
>> cooling, if it conducts through the first fast enough. I'm referring to
>> the type with the fan on the side.
>
> Call me, when your solution uses heatpipes.

It does.  Two coolers, each with their own 4 heatpipes.

> Look at the Zalman completely-passive cooling
> computer case, if you want to see how to do it.
> It moves heat from one place to another with
> heatpipes. The exterior of the case is the
> final destination.
>
> https://www.quietpc.com/tnn500af

No no and no.  I once bought a "silent power supply" that threw it's heat out the back with a sticky out heatsink.  It went bang after a few months.

> Only with heatpipes, can you move heat from
> the origin, to the second heatsink, and expect
> to get improved performance.

And both the heatsinks have heatpipes running through them.

> That's why heatpipes are used, between baseplate
> and top-of-fins, so that an excessively-long fin
> does some work for you.
>
> It's also why a 50mm tall 40mm square heatsink,
> is no more effective than a 25mm tall 40mm square heatsink.
> Those are used on chipsets. The upper portion of the
> taller unit, has insufficient thermal conduction
> for the top of the fins to remove heat. It means
> making fins longer and longer (without heatpipes),
> is asymptotic. At some point, a longer fin adds
> nothing to the solution.

I can't believe that, metal is a very good conductor.  The top of tall ones can still be hot to touch.

> Once you lace the parts together with heatpipes,
> then we'll talk. There's a limit to how many
> heatpipes can be fitted, and some thought has to be
> put into where the heatpipe is moving the heat.

I would have 4 heatpipes running through the bottom half, and 4 through the top half.  There would only be a short interface of normal metal to join the two.

> You place the heatpipe at the source, as only if
> the heatpipe is in intimate contact, does its 1000x
> better performance, work. Just ramming a pipe into
> a block with 3 inches of aluminum between the
> baseplate and the pipe, that would be useless too.
> As the 3 inches of aluminum is a huge thermal
> resistance, and the zero resistance of the heatpipe
> on top cannot then help. The heatpipes always start
> in the baseplate, touching the CPU.

Doesn't have to.  The top of the existing heatsink is too hot to touch.  So the heatpipes on the new heatsink will take heat away from there.

> This is why we buy a larger heatsink, like a Noctua.
> Instead of impishly welding stuff together, the
> heatpipes on the properly-designed unit, have been
> selected for the perfect location to get the
> best effect. While the unit may be designed with
> two fans, it works quite well with only the
> central fan fitted.
>
> Heatpipes have non-linear behavior. If you pump too
> much heat into them, the liquid-vapor phase transfer
> stops because all the materials remain in the vapor
> phase. The manufacturer will usually suggest a max
> power as a practical limit (before the pipes saturate
> and the degree-of-cooling ends up actually reduced).
> If you put six pipes in parallel, as soon as one
> pipe saturates, the other five carry the load and
> then they drop in quick succession.

What temperature should the CPU be for optimal heatpipe cooling?

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Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-25 19:01 +0100
  Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-25 16:52 -0400
    Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-25 22:37 +0100
      Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-25 18:01 -0400
        Re: Has anybody ever stacked two CPU coolers? David_B <DavidB@nomail.afraid.org> - 2020-07-25 23:08 +0100
          Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 00:31 +0100
            Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-25 19:41 -0400
              Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:25 +0100
                Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-26 10:40 -0400
                Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:43 +0100
                Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-26 11:38 -0400
                Re: Has anybody ever stacked two CPU coolers? David_B <DavidB@nomail.afraid.org> - 2020-07-26 17:32 +0100
                Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-26 16:13 -0400
                Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 22:18 +0100
                Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-26 19:21 -0400
                Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 18:06 +0100
                Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-26 16:14 -0400
                Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 22:17 +0100
                Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-26 19:26 -0400
          Re: Has anybody ever stacked two CPU coolers? Wolffan <akwolffan@zoho.com> - 2020-07-25 19:32 -0400
        Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:20 +0100
          Re: Has anybody ever stacked two CPU coolers? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-27 11:32 +0200
            Re: Has anybody ever stacked two CPU coolers? Rene Lamontagne <rlamont@shaw.ca> - 2020-07-27 08:59 -0500
              Re: Has anybody ever stacked two CPU coolers? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-27 22:59 +0200
      Re: Has anybody ever stacked two CPU coolers? Avila Kap <kap0utox01@jamaica.com> - 2020-07-25 16:52 -0700
        Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:38 +0100
  Re: Has anybody ever stacked two CPU coolers? Paul <nospam@needed.invalid> - 2020-07-25 18:33 -0400
    Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-25 23:47 +0100
      Re: Has anybody ever stacked two CPU coolers? David_B <DavidB@nomail.afraid.org> - 2020-07-26 00:17 +0100
        Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 00:30 +0100
        Re: Has anybody ever stacked two CPU coolers? Snit <usenet@gallopinginsanity.com> - 2020-07-25 16:57 -0700
          Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:35 +0100
            Re: Has anybody ever stacked two CPU coolers? Snit <usenet@gallopinginsanity.com> - 2020-07-26 10:22 -0700
              Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 19:44 +0100
                Re: Has anybody ever stacked two CPU coolers? Snit <usenet@gallopinginsanity.com> - 2020-07-26 11:46 -0700
      Re: Has anybody ever stacked two CPU coolers? Chris <ithinkiam@gmail.com> - 2020-07-26 10:16 +0000
        Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:35 +0100
          Re: Has anybody ever stacked two CPU coolers? Chris <ithinkiam@gmail.com> - 2020-07-27 07:05 +0000
            Re: Has anybody ever stacked two CPU coolers? Paul <nospam@needed.invalid> - 2020-07-27 05:14 -0400
              Re: Has anybody ever stacked two CPU coolers? Chris <ithinkiam@gmail.com> - 2020-07-27 18:12 +0000
      Re: Has anybody ever stacked two CPU coolers? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-26 13:27 +0200
        Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:34 +0100
          Re: Has anybody ever stacked two CPU coolers? "Carlos E.R." <robin_listas@es.invalid> - 2020-07-26 20:50 +0200
    Re: Has anybody ever stacked two CPU coolers? Rene Lamontagne <rlamont@shaw.ca> - 2020-07-25 19:43 -0500
      Re: Has anybody ever stacked two CPU coolers? Paul <nospam@needed.invalid> - 2020-07-25 21:45 -0400
        Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 15:29 +0100
          Re: Has anybody ever stacked two CPU coolers? Paul <nospam@needed.invalid> - 2020-07-26 13:46 -0400
      Re: Has anybody ever stacked two CPU coolers? "wasbit" <wasbitREMOVE@hotmail.com> - 2020-07-26 10:03 +0100
  Re: Has anybody ever stacked two CPU coolers? Peter Johnson <peter@parksidewood.nospam> - 2020-07-26 17:01 +0100
    Re: Has anybody ever stacked two CPU coolers? "Commander Kinsey" <CFKinsey@military.org.jp> - 2020-07-26 18:05 +0100

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