MSI MEG X870E GODLIKE - USB4 & M.2_2 Bifurcation

There's an item "ASM4242/M.2_2 Switch" in the BIOS of the flagship MSI X870E GODLIKE. What's this item for?

On MEG X870E GODLIKE, the rear USB4 ports and M.2_2 slot share the PCIe 5.0 x4 lanes from CPU. But MSI make them work simultaneously.

When the M.2_2 slot is populated with device, both USB4 and M.2_2 slot are running at PCIe 5.0 x2. When there's no device on M.2_2 slot, USB4 will support PCIe 5.0 x4.

You can decide to let the M.2_2 slot run at PCIe 5.0 x4 by adjusting "ASM4242/M.2_2 Switch" to "M.2_2 x4", at the cost of USB4 disabled.