PCIE slot configuration in bios?

Echo Express Thunderbolt to PCIe Card Expansion Systems pcie slot dimensions What types of PCI Express slots and sizes are there, and what to PCIe lanes mean? · PCIe x1: has 1 lane, 18 pins, and 25 mm in length · PCIe x4: pciex1_1 slot A PCIe x16 slot by definition is a slot that will take a PCIe card with up to 164 pins and up to 89mm in connector length (Cf the Wikipedia

pcie slot x16 PCIe Slots ; Slot 3 CPU 1 PCIe x16 x8 ; Slot 4 CPU 2 PCIe x16 x16