AM5 board supports PCIe Gen 4x16 and Gen 3x8 expansion slots.
AM5 board supports PCIe Gen 4x16 and Gen 3x8 expansion slots.
Usually it's not possible since the channels are permanently set up, meaning you can't simply swap a generation level to make room for additional lanes.
It's costly. For instance, this board will accommodate x16 Gen5 tracks and divide them into x32 Gen4 tracks. The price is $1250. https://c-payne.com/products/pcie-gen5-m...ec-pm50052