Blurry simulink block title/text

I have a problem during switching from 2011b to 2013b.

Why is the text of block in 2013b so blurry comparing to the old 2011b? See pic below, same font size, same zooming.

Is there any solution or setting that I am missing?

thanks

Song

[Walter Roberson]

Are you using a high resolution display, or do you have a high resolution display connected?

[Song]

I am just using a normal windows PC with resolution of 1920x1200 not a 4K or UHD