The WX5100 has a small blower fan and 4 regular Display ports. All of the ports work but only 3 simultaneously. The card is quiet and report 27W at most (so it’s not maxing out it’s power). It runs off PCIe power only (no extra power connector). I run the O6 in a standard mITX case with a PCIe riser and SFX power supply. This combo is noise less - what you do hear is the CPU fan kicking in once in a while.
I tried a RX6400 briefly but no success - might work now. The 6400 is Navi and PCIe4. My riser does not run stable with PCIe4 (even on x86). The Polaris cards work well so I am sticking with those. The WX5100 was $79 on eBay.
As for NVidia, the GT710 worked well (I have one with PCIe x4 and one with PCIe x1 - so these are filler cards, really). Both are PCIe3. Oh, yeah, the GT710s are a fan less. I also have a RTX4060, that is PCIe4 and I stuck it in, didn’t work and didn’t bother troubleshooting. I have a couple more Navi2 cards.
My main focus is running my office off grid (solar+batteries) and with what I have (O6 50W) the focus is on power consumption not performance primarily. And that combo fits the bill. Great performance (really great) for that power envelope - did I say dacapo java bench runs 10%+ faster in this (8 core) than it does on an i7 4790@4.7GHz and 105W. Yeah, that fast. And without GPU you’d look at around 35W for the O6.
One more thing. I’m not running AMDGPU, but standard built in drivers+mesa. Not hacks or custom installs. I do run the Latest (1month old?) EDK2 UEFI Bios, though - what I just noticed - I run the Radxa System Ready BIOS (9.0.0) in ACPI mode not the “official” Radxa BIOS 0.3.1.