Can PCIe x8 Fit Into x16 Slots?

Can PCIe x8 Fit Into x16 Slots? pcie x4 in x16 slot Expansion slots: 1x PCIe x16, 1x PCIe x4, 1x PCIe x1 Video ports: 1x DisplayPort 1x HDMI USB: Up to 1x USB Gen2x2 pcie 50 x16 slot 1 x PCIe x16 slot Intel® B760 Chipset 1 x PCIe x16 slot 1 x PCIe x1 slot

pcie 50 x16 slot It'll have all 16 if you don't use the second slot but it makes no difference Even a 1080 shows no performance difference at x8

pcie x 16 slot PCI Express Expansion · Five PCIe Gen 4 x16 Slots One PCIe x16 Slot for Target Cable Adapter; Four PCIe x16 Slots for Add-in Card · ATX Pci express x16 vs x8 vs x4