There is one flaw in his setup, he doesn't seem to cool the VRMs of his video card (only memory chips). Not doing that is asking for trouble when load is put on the card.
For these cards the giant heatsink is connected to the VRMs so cooling is a non issue. In OP's pictures, he seems to have replaced the heatsink of his card with one from the case without cooling the VRMs.
From personal experience, I tried to silent cool an RX 550 (50 watt vs 75 watt of 1050 ti) without VRM heatsink and the VRM temnperatures were up to 100-103C during a torture test. Adding a fan lowered the temperatures by 20C.
Both the hi-side and lo-side mosfets (they might be 2in1 on a card like this) are rated for their amperage at 125c and are typically capable of dissipating that through their contact with the pcb. Airflow is nice, but not required. Neither is direct contact with a heatsink. Those are for higher end cards (who also rate their mosfets at 125c for good reasons. Max tCase for mosfets is usually 150c. Beyond that they just die.
If I remember correctly that card still needs some air flow to work, normally provided from case fans. That would be problematic in a completely fanless system. A Ryzen APU might be better, as the case would cool it.
The design of the DB4 is such that the graphics card is mounted vertically. Fresh, cool air flows in through the grille at the bottom, over the VRM area, then up and out the top of the case.
I have more small heat sinks I could put on the mosfets, but they are relatively low profile so I'm not sure they would improve things much.
A single, large heat sink, with long fins (that would protrude above and beyond the nearby capacitors) would seem to make more sense — but given there are no mounting points I could use to clamp it down I'd be a bit concerned about the long-term effect of torque.
Correct. I did the same thing with RX 560 and it died within 2 weeks even though "GPU temp" was never above 60C (normal desktop use, I never gamed on it).
