It depends on where the words and boxes come from and when in the process you're seeing them. Some final output codecs will make text and lines look bad, interlacing can also make them look bad. The traditional way of dealing with it has been to make the objects bigger and to use softer edges on them. Color and brightness can also be an issue, depending on the type of output. Red text in DV25 is a good example of ugliness.
It's very unlikely to be caused by your video card. Even if by some exceedingly unlikely chanceit is, then it shouldn't be affecting the final rendered videos.