Mine is not down sampled but wont display at native 1360x768 resolution via hdmi. It does support resolutions such as 1280x768 but that leaves black borders at the sides as it does not stretch the picture. Using resolutions such as 720p, 1080i, 1080p etc also leaves borders or causes fuzzy text on the KDE desktop but is fine for video playback or orbiter text.
I have found that VGA input gives me the best of both worlds, i.e. perfect monitor capability and excellent quality when viewing moves