1 x gen3 x8 slot (x4 link)
Can PCIe X4 Card Fit in X16 Slot? - Can it Work? - PC Guide 101
For x670e, the max PCIe slot configuration implemented by vendors is 3 slots with x8,x8,x4.
PCIe Cable for industrial systems - BRESSNER Technology - Shop
Competent IT partner for PCIe cable ✓ up to 300 meters ✓ PCIe x8 / x4 optical cables ✓ PCIe x16 copper cables ✓ Get your inquiry!
Using an eGPU with a mini PC - CNX Software - cnx-software.com
A prototype GPU from Colorful featuring two M.2 SSD storage slots ... The company has divided the remaining x8 lanes, allocating x4 lanes to each SSD slot via PCIe bifurcation.