hello,
it is possible to install the drivers of pci-ex giga lan on routerOS Mikrtotik 2.9.x/3.x?
becouse that lan on board of materboard "ASUS P5LD2-X" doesn't see it
best regars
serenda

No, it is not possible to install additional drivers.
If the cards is not recognized, it means currently it's not supported.