What is the meaning of the blue PCIe slot on the Dell T7910

On the motherboard, PCIe lanes appear in x1, x2, x4, x8, and x16 variations More lanes mean more bandwidth, as well as a longer slot GPUs are usually

There are two full PCIe X16 slots The blue is the primary one

pcie x1 slot function The slot capability is required for Root Ports if a slot is implemented on the port Slot status is recorded in the PCI Express Capabilities register

pcie m2 slot The riser card shown in Figure 2-14 is installed in IO module 1 It can house two full-height half-length x8 PCIe standard cards in