The 0-1 space in your UV map has a 10 x 10 grid. If the texture map you are using is 1024 x 1024 then each of those squares is 1024/10 or about 102 pixels.

The area you have outlined is about 1 x 4 squares. If that was applied to a single planar surface then on a 23" screen it could not be more then 1 x 4 inches without texture stretching. However, it does not appear to be a single planar surface it looks like a surface that has been unwrapped and the largest planar surface I see in about the size of a single square in the 0-1 space, which is about 100 x 100 pixels or about 1" square on a 23" monitor without texture stretching.