I use my motherboard with a DVI monitor, and it works just fine. Recently I bought a TV which I connected by hdmi. The TV automatically recognizes the signal (1920x1080p 60Hz ) and looks fine at first, but when something rapid is happening on the screen (fast-paced movie, game, or simply dragging a window across the desktop), the picture just "splits" horizontally.
It's quite hard to capture it but somehow I've manage to;

When connecting any other device (tablet, telephone, camera) through hdmi, everything's fine.
(Could buying a video card solve my problem?)