Embodiments of the invention relate to polycrystalline diamond compacts (“PDCs”) and methods of fabricating such PDCs. In an embodiment, a PDC includes a substrate and a preformed polycrystalline diamond table including an interfacial surface bonded to the substrate and an opposing working surface. The preformed polycrystalline diamond table includes a proximal region extending from the interfacial surface to an intermediate location within the preformed polycrystalline diamond table that includes a metallic infiltrant infiltrated from the substrate, and a distal region extending from the working surface to the intermediate location that is substantially free of the metallic infiltrant. A boundary exists between the proximal and distal regions that has a nonplanar irregular profile characteristic of the metallic infiltrant having been infiltrated into the preformed polycrystalline diamond table.