Types of PCIe Slots PCle Lanes

What is the meaning of the blue PCIe slot on the Dell T7910 pcie slot meaning For instance, Port 2A-D on CPU0 corresponds to physical Slot 6 , the top PCIe slot on my motherboard where I have my GPU plugged in While pciex1_1 slot A physical x16 slot can run at x4 theoretical speeds depending on usage and wiring It's why with multiple graphics card set ups you may see

pciex16 slot configuration PCI vs PCIe Slot · PCI-E x16 slot: It is 89mm long and has 164 pins It is often used for graphics cards and backward compatible with x1 x4