I want to understand how PCIe lanes are shared on my motherboard

PCIEx16 drops to x 8 when M2 SSD is installed??? m 2 slot with pcie x4 lanes Manufacturers can use the PCIe lanes to implement other fast components on their motherboards, like Ethernet, Wi-Fi, or additional NVMe m2_1 slot to allow 2 NVME drives to run in a PCIE x4 slot on a board without lane bifurcation (uplink is x4 and the card's config implements 2 x4

m2 nvme slot The CPU does indeed have 16 lanes However the Chipset has additional PCIe lanes to manage devices aside from the GPU such as the SSD Z270 has 24