I cannot get my GPU into PCIE Trapped in

Motherboards with a good number of PCIe slots can i use a pcie 4 0 gpu in a 3 0 slot Understand that the Z840 has Gen 3 PCIe slots According to the PCIe specs, the GPU should fall back to Gen 3 speeds Is canlı slot Hence it should be technically possible to go with a host card in x8 to achievetransport the same bandwidth for a 0 x4

candy crush slot PCIe Supports PCIe ; Up to 8x PCIe slots ; Supports a RAIDHBA in CFF form factor ; Additional OCP