I'm using a Samsung UE55KS7000. When using MADvr with MPC-HD, setting display to advanced color mode will display some LG & Sony HDR tech demos properly (LG Cinematic Jazz HDR10 is amazing when displayed properly), but others are completely fucked up black & blue colors or have highlights clipped. The whole win10 desktop looks dark and washed out. Windows Built in Movies & TV app seems to be the best & most stable for HDR playback, but it will sometimes lock you to certain audio languages and has shitty subtitle support. The Nvidia forums and AV forums are filled with complaints about these issues.