Ah yes this, a cluster of 1000 of those the only problem with this is that raspberry uses old SoC from 4 years ago or so If I'm not what I call efficient by any mean, but if a similar solution with let's say a Qualcomm Snapdragon 835 or a Tegra X1 or something similar could do wonders and beat out a out RX Vegas in specific operation since an RX vega consumes between 250 and 300W around 20 of those could consume the same amount of power as a thousand and this without counting the power consumption of the boards cpus and other components, I'd say 15 Vegas is a more realistic number vs a cluster of a 1000 of those so that's a ratio of around 67 SoC per Vega card.

Now the question that should be asked is, is a Vega 56 is more powerfull than 67 X1 for example, the X1 is 1Tflops of peak 16FP calculation where as the Vega around 21 Tflops which means that the Cluster has more potential than the Vega cards, but the software to take fully advantage is not there.


And the big elephant in the room is that  I'm not factoring the costs, obviously the amount of work and the price of component is in favor for the classic mining rig with vega cards. so Tl;dr, the ARM route can be more powerefficient if the software is there, but it is right now just more expensive and not fully optimised to be the better solution for mining. but for other use cases it is much more interesting.