mac slot

What are the specifications of the PCIe slots? If you look at the expansion slot utility, you will see these are the specs of each slots: Slot 1: gen4, up to x16 lanes Slot 2: gen4, up to x16 lanes Slot 3: gen4, up to x8 lanes Slot 4: gen4, up to x8 lanes Slot 5: gen4, up to x8 lanes Slot 6: gen4, up to x8 lanes Slot 7: gen3, up to x4 lanes divo slot