Node Duo - Thunderbolt 3 PCIe expansion chassis for 2 cards

The x1 slot you used was probably on the PCH and not direct to the CPU Plug it into one of the

Node Duo - Thunderbolt 3 PCIe expansion chassis for 2 cards Two types of PCIe slot on an Asus H81M-K motherboard Various slots on a computer motherboard, from top to bottom: PCI Express x4; PCI Express x16; PCI Express

The x1 slot you used was probably on the PCH and not direct to the CPU Plug it into one of the

twin33 slot Dual T3 to 1x PCIe External Box HighPoint 6661A · HighPoint Sonnet Echo II DV Module, Two PCIe Slot, 40Gbps Thunderbolt Port, 400W PSU LN147156

Do at Your Own Risk Installing an external GPU can void your warranty, because this tutorial

external gpu slot RESET · TB31PCIEX16 Thunderbolt 3 PCIe Expansion Chassis

One slot utilizes a PCIe x4 interface for blazing-fast storage external displays, a DisplayPort port for another display