Pixel density
A display’s pixel density is the number of pixels packed into a specific portion of a display (usually per inch or, in some cases, per centimeter.). More pixels per inch will translate to a sharper image that can better render fine details. That’s important for PCs, which often rely on small fonts and small buttons that are difficult to render smoothly.
Because pixel density is based on pixels per inch, rather than overall resolution, large televisions score poorly in this area. A 42-inch 1080p display will have a density of 52ppi, for example, while a 60-inch 1080p display offers a much lower density of 36ppi. That means the 60-inch display will appear to render small details and fonts poorly relative to the smaller television.
In theory, the low pixel density of the 60-inch set won’t be noticeable if the user sits at an “ideal” viewing distance, but reality is often not so forgiving. This is because PC fonts are sometimes so small they’re impossible to read at the recommended viewing distance for a large HDTV (which can range 6 to 10 feet, depending on size). In general, it’s better to sit close to a (relatively) small, high-density display than it is to sit far away from a large, low-density television.