This is not normal. I use a cheap laptop with an integrated card and the image is superb on my HDTV (I use a HDMI cable). Since you have a Quadro FX 580 you probably have many different output behind the card. Did you try to connect it directly with a HDMI cable? If the card doesn't have a HDMI output you probably have a displayport instead, so you could try a displayport-to-HDMI adapter maybe it will work better. I would advise against using VGA, or just use it as a last resort because it is likely to give an inferior image quality on a HDTV compared to displayport, DVI or HDMI.