Jouni Osmala (fname.sname.delete@this.aalto.fi) on August 15, 2019 5:58 am wrote:
> Adrian (a.delete@this.acm.org) on August 15, 2019 3:47 am wrote:
>
> > In conclusion, while for small computers I also always attempt to use only fanless computers,
> > for large computers I do not believe that it is worthwhile to accept the much larger
> > size & weight that is required for a fanless computer at any given TDP.
>
>
> I disagree about the size but not about the weight, which is mostly dependent on personal fitness. I
> measured the extra volume my cramped midtower case made by nexus takes to insulate better for noise.
> Convection heatsink of that size can emit 25W per degree of difference between ambient and the heatsink.
> Assuming ambient around 20C, you can emit atleast 750W with reasonable temperatures for the components.
> This assumes fanless system design, not trying to put fanless individual components inside the case,
> but use heatpipes to transfer the heat to the case side panel which operates as heatsink.
> Compulab airtop3 has high enough total power in a very small form factor that scaling
> its gpu 160w heatsink to 250w and upgrading CPU heatsink to that wouldn't make it particularly
> large design. Here's its comparison to other small form factor PC:s.
> https://www.youtube.com/watch?v=35OyZzCvG0g&t=1m22s



Where I live there is no doubt about climate warming, so I must assume ambient of 40C, as such temperatures became not infrequent during summers.

Nevertheless, I agree that with side panels of the Airtop type, you might be able to dissipate 750 W without a huge case, but you will have to be very careful to never touch the case, because it will be quite hot.


However, for now, Compulab Airtop is a unique fanless case on the market. All the other available fanless cases, including those shown at the link provided by you in your previous post, are much larger for a given TDP than a case with active cooling.

Also, if I would be willing to spend enough time, I could make in my home a case equivalent to or better than any other fanless case that I have ever seen, except Airtop, by cutting, milling and assembling extruded aluminum or copper profiles.

I could not duplicate Airtop, because I can make neither the side panels nor the complex heat pipes with simple tools.

For some reason, no other company attempted to clone Airtop, either because this design is protected by patents or because they believe that this market is too small.


Compulab Airtop is the only fanless case that does not have a size disadvantage at the power levels required for a decent desktop, but because it has only a single source, it has serious disadvantages:


1. If you buy one now, there is no guarantee that in a few years you will be able to buy another one, to be able to replace or upgrade it. If you could be forced to revert to a traditional Mini-ITX in the future, it does not make much sense to become spoiled by using an Airtop now.


2. If you happen to need certain features that do not exist on the current Airtop model, there is nothing you can do about it. With standard motherboard formats like Mini-ITX, there are good chances that you will find some model with what you want.

The first 2 Airtop models used components that were somewhat obsolete at the date of their launch, so I was never tempted by them. On the other hand, the current Airtop 3 is very attractive, because it includes excellent components and it also has enough I/O ports for the needs of most people.

Unfortunately, I could not use it, because I need both a good GPU and 10 Gb/s Ethernet, while Airtop 3 provides either a discrete GPU or 10 Gb/s Ethernet, but not both. With Mini-ITX, there are a few models which have what I want.


3. Airtop 3 is as expensive as the best mobile workstations (which also include a lot of peripherals, e.g. display, KB, camera &c.).

I must have at least one expensive laptop, for business trips. The main reason for also having a desktop is that it can be more powerful than any laptop at a much lower price. If I could afford to pay the same price for the desktop, then I would better buy a second identical laptop instead of the desktop. The lower performance would not be so important, because I also use some servers, and I would have more peace of mind due to having an identical backup laptop in the case when the other becomes defective or is stolen. (Now I buy a new laptop before the old becomes unusable, so the old laptop is the backup laptop.)




While an Airtop 3 would not be a good choice for me, it is a design that I admire for 2 reasons:

1. Its cooling concept, with the lateral panels with vertical holes which ensure a strong air flow due to convection and with the heat pipes that ensure a good spreading of the heat over all the surface of the panels is indeed the best that can be done for a fanless case.


2. The small volume of the case is due to the fact that the CPU card and the GPU card are sandwiched. This is the best way to make a system with only 2 cards.



Unfortunately, when Mini-ITX was introduced, it was designed to be able to use the existing ATX cards, regardless if the right-angle configuration of the cards wastes a lot of space.


A conventional Mini-ITX case that accepts full-size GPUs cannot be smaller than about 11 ... 12 L.

To reduce the size down to 4 ... 8 L without requiring the use of half-height GPUs, you must change the configuration of the CPU & GPU cards to either planar or sandwiched.

For this you must either use standard motherboards together with a PCIe extender (which increases the cost and lowers the reliability), like in e.g. the A4-SFX case, or you must use non-standard motherboards, like in Compulab Airtop 3 or in the upcoming Intel Quartz Canyon & Ghost Canyon.