I am encouraged by the creativity of this forum Great work.
But, the withdrawal of GPU mining in the near future, why is no one designing a board that will plug into the empty PCIe slots? I would think a 2 to 8 chip board with cooling would be a perfect fit, as power is right there with the unused PSU connector from the retired GPU. This might be a future consideration, as I see the small boards as expensive in relation to larger boards, price per square CM per hash rate.
What are your thoughts?
* USB is a much simpler (and cheaper) interface to work with than PCI-E for development of this type
* A single host computer can have a lot more USB devices connected to it than PCI
* The host doesn't even have to be a PC- it could be a raspberry pi or TP Link router
* The boards in development now use the PCI-E power connectors anyway that GPU's use