What is LCD Native Resolution
The physical structure of some types of displays, including LCD Monitors/TVs and plasma panels, defines how many pixels can be displayed at once. The display produces the sharpest picture when used at its so-called native resolution. This is the physically number of horizontal and vertical pixels that make up the LCD matrix of the display.

Setting a computer display to a resolution lower than this resolution will either cause the monitor to use a reduced visible area of the screen or it will have to do extrapolation. This extrapolation attempts to blend multiple pixels together to produce a similar image to what you would see if the monitor were to display it at the given resolution but it can result in fuzzy images.