No, it is a U.2 HBA. U.3 drives will work on U.2 controllers (at slower PCIe 3.x speeds), but not vice versa. All the pinouts and backenplanes, etc. are what confuses me. It should be possible to connect 4x U.2/U.3 drives or 2x U.2/U.3 drives and up to 8x SATA/SAS if I understand correctly.