A framerate/refresh rate mismatch like this will result in one of two problems: 1: Frame judder, as a result of some frames from the 50hz content being display

A framerate/refresh rate mismatch like this will result in one of two problems: 1: Frame judder, as a result of some frames from the 50hz content being displayed for more refresh cycles than others. 2: Image tearing, which is caused by the content being updated in the middle of the 60hz refresh cycle. Ideally you want the framerate of your content to be an even factor of the display's refresh rate. So for a 60hz display, that means you want the framerate of your content to be 60, 30, 20, 15, etc.