Contrary to what usually happens in Windows, vsync is forced in fullscreen mode for Witcher 3 but not in windowed or borderless mode. Vsync is off in AMD settings and game settings, frame rate is uncapped and fullscreen enabled in game settings as well. I only intend to play in fullscreen mode because the other modes have a significant performance impact in my case. I have an HD 7970M inside a Sager NP9150 laptop, latest Intel and AMD GPU drivers. Windows 10 64-bit fully updated.