Anandtech checked out the MSI X299 XPower Gaming AC
A quote from the article:
MSIs 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.MSI X299 XPower Gaming AC Review
Previous generations of MSI XPower models were primarily focused on extreme overclocking and enthusiasts looking to wring every last MHz out of their CPU. The boards were designed with enough power delivery to be able to handle just about anything thrown at it, as well as some overclocking only accessories. As time has moved on, we have seen the line start to blur the markets between overclocking, enthusiasts, and gaming, and now we have crossover boards, such as this one, which combine the feature sets.