Asrock B150M PRO4/D3, Lga1151 Matx Mb, Supports 6th Generation Intel Core Processors (Socket 1151), 2 PCIe 3.0 x16, 1 PCIe 3.0 x1, 1 PCI, Graphics Output Options: DVI-D, HDMI, 7.1 CH HD Audio (Realtek ALC892 Audio Codec), ELNA Audio Caps, 6 USB 3.0 (2 x Front, 4 x Rear). Actual memory size may be less than 4GB for the reservation for system usage under Windows® 32-bit OS. For Windows 64-bit OS with 64-bit CPU, there is no such limitation.