MSI’s flagship motherboard for HEDT the X299 XPower Gaming AC. The XPower Gaming AC pulls from its overclocking and enthusiast pedigree as well as including features more focused on gaming, designed to attractive to an even broader audience. MSI also focuses on storage, including U.2 support and the ability to use five M.2 devices out of the box. 

Source: AnandTech – The MSI X299 XPower Gaming AC Review: Flagship Fantasy