https://www.theverge.com/2018/5/30/17408610/asus-crypto-mining-motherboard-gpus

Asus announced the H370 Mining Master motherboard today, which is specifically designed for cryptocurrency mining. It supports up to 20 graphics cards — yes, 20 — along with streamlined connectivity by allowing USB riser cables to plug directly into the PCB over PCIe.

Asus’ approach here is going to make maintenance easier, ensure fewer PCIe disconnects, and more accurate diagnostics. This is a better format than just plugging in graphics cards to the motherboard via PCIe, like you would in a gaming desktop, the company says.