Before the video stream is sent to the monitor, Nvidia cuts out unnecessary colour information to make the actual stream smaller in size, opening up enough bandwidth to fit in a 60Hz stream over the regular HDMI 1.4a interface.
Although nothing in the actual images is affected, there is the issue of colour loss. Chroma subsampling essentially reduces the range of colours that appear in the resulting video stream, which can be problematic for video content that has very dark scenes, or lots of colour in fine details.
Intersante... o sea que comprime la información para que "quepa" en el ancho de banda del cable... Me pregunto si hay momentos de juego en el que no pueda comprimir, y empiece a fallar (parones o pérdida de detalle/color/degradados, etc...).