2018 Mac Mini [8th,6C,B] + RX 570 @ 32Gbps-TB3 (Zotac AMP Box Mini) + macOS 10.14.5 [steve4332]  

@steve4332 Thank you for sharing this build. Very nice work fitting the 140mm cooling fan! I use the RX 580 out of the Gigabyte Gaming Box (130mm fan) and it's quiet. Your custom cooling should be silent by comparison. We'd love to see a side-by-side with the Mac mini. Perhaps custom cooling for the Mac mini is next. 😀 

Nice to see more pics of the Zotac mini box... also love the GPU mod - I've often considered whether the shrouds are really needed in eGPU's, might look into running my Vega shroud less as it should help with cooling a bit (not sure if that's even possible).

As @itsage said, would love to see some side by side / full set up shots, although it might tip me over the edge of buying one of these....

Here are some additional photos for size comparison to the Mac Mini. I think astethics-wise the two units don't go very well together, so I keep the Zotac Mini hidden away under my desk... The Zotac Mini is obviously not so mini compared to the Mac Mini.

As you might see, there is a blue smear behind the Zotac box on the wall. It is caused by the light of two rather bright blue internal indicator LED-s soldered to the Zotac Mini's motherboard leaking through the vent holes. At night it can be a nice wallpaper effect or annoyance (depending on what level of darkness one might prefer). I did some close ups of the green and red LED in the front (red is the off state, green is the on state) and the blue LEDs leaking through the vent. During standby only the green LED remains on, the blue LEDs turn off, so if you have your system in your bedroom it will not cause any annoyance.

Finally, here are some screenshots - to show how the unit shows up at System Preferences. Also a printout of the fan speed at the default 37% PWM fan level using the Arctic P14 fan (this is when the cooling kicks in during normal desktop usage when the GPU temp reaches 55C - the fan turns off completely after the temperatures go below 45C). The fan cannot be controlled under MacOS, but I tried removing the fan altogether - the temperature then just keeps increasing to a dangerously high 80-85C even showing a completely blank screen without any movement, both the GPU and memory at the lowest speed step - this means that the Sapphire RX 570 ITX cannot work at all in passive mode without the fan kicking in periodically at normal room temperature.

The fan spins at 680-690 RPM which is impercetible even if I put my ear next to the unit at night. The original fans have an audible kick-in sound, but luckily the Arctic fan spins up absolutely gracefully without any audible noise whatsoever.

ps. in order to claim my AMD rewards for purchasing the RX 570 I had to run the AMD product verification tool which works under Windows only. Therefore I had to attach the eGPU unit to my Windows PC (which is also thunderbolt equipped thanks to the ASRock Phantom Gaming ITX motherboard). I did not experience any issues, after I installed the Intel Thunderbolt software downloaded from ASRock and the Radeon drivers, everything went smoothly (Windows 10 ver 1903). I didn't experiment with it much however, since the PC has an RTX2070 card which is more powerful obviously.

Lovely clean full set up!
Do you have a link to your mobo? Thinking of building a mitx set up.

This is the mobo:

Z390 Phantom Gaming-ITX/ac

It's a really decent board, packed with features. But it's Thunderbolt is PCIe x2 only (Intel JHL6240), which limits its speed. 🙁

I updated the original post with pictures of my various fan mod attempts.