Log Completely Passive SFF Build

[dawizard]

This is probably a stupid idea for my first even SFF build, and I doubt I will be able to completely achieve it on my first try. The idea behind building this system is that by running Ubuntu LTS 22.04 on modern passively cooled hardware I should be able to achieve reasonable performance for linux development work with literally no noise.

Here's a rough draft of the system specs:

• iCPU: 3-12100 (I could downgrade this to a Celeron G6900 or Pentium Gold G7400 if it proves too hot)
• Cooler: Passive CPU Cooler (I'm having trouble finding one with only 72mm of CPU Cooler Clearance)
• RAM: G. Skill Trident Z RGB (2x8, DDR4 3600 CL 16)
• Mobo: ASRock Z690M-ITX/AX
• SSD: Intel 670p 1TB Nvme (Two)
• GPU: Matrox Luma A310 (This is a passively cooled, low profile, 75w intel arc card, so far I can only find it for ridiculous enterprise prices i.e. $500)
• Case: Lazer3D HT5 (Which should be avalible in November or so if I heard correctly)
• PSU: HDPlex 250W Passive

My powe draw estimate was ~ 185W (90W CPU Max Throttle, 75W GPU, 20W for general system)

As a newcomer to the SFF space, does this build seem reasonable? And does anyone know of any LGA 1700 Passive cooler that requires less than 72mm of clearance?

 

[REVOCCASES]

My powe draw estimate was ~ 185W (90W CPU Max Throttle, 75W GPU, 20W for general system)

You won't be able to (fully) passive cool that in a case like the HT5 - even if you install two case fans I doubt you can run the CPU at 90W PL (PS: the GPU you mentioned is limited to 30W and still needs a bit of airflow)

To get a rough idea how much cooling (surface) you need to get rid of that power, I'd check some other fanless/passive builds first. For example:

 

[msystems]

Personally I would recommend Streacom FC5 Alpha, it comes with the hardware to properly conduct your cpu heat into the chassis. I did a lot of testing on it and the chassis itself can dissipate like over 200 watts (over the entire surface area). But I would only recommend going this way if there is no gpu or a very very weak gpu as it is not designed properly to operate with a GPU. Since the case does not come with hardware to also dissipate the GPU heat passively, any GPU waste heat will become completely trapped inside the case.

There is also a passive HDPlex case (H5) which does allow you to passively dissipate cpu+gpu but they have not updated the GPU hole pattern mounting in 3 years. Thus you can only use the gpu mounting hardware with GTX 1080 Pascal and older. But the mounting brackets are current for CPUs.

IN terms of Streacom vs. HDPlex, well, the hdplex case, while not being as beautiful of a design as Streacom on the outside, completely nailed it on the thermal interface side. Overengineered and can transfer hundreds of watts (more than this case can handle, by far).

By comparison, the thermal interface hardware on Streacom is garbage. It uses an aluminum plate and half the heatpipes.


If you want to use a case that isn't designed for passive cooling, it will need to be pretty large since the only real option is the Noctua NH-P1

NH-P1

The NH-P1 is Noctua’s first passive CPU cooler and has been custom-designed for fanless operation from the ground up: in enclosures with good natural convection, its six heatpipes and thick, widely spaced heatsink fins enable it to cool modern high-end CPUs with low to moderate heat dissipation...

noctua.at

There's a few open air (X-Proto) passive builds using the P1, seems to work decently.