Probably the fact that you have the text DPI set to 150% (Larger).
And that Windows sucks at scaling.
At least it has OS level scaling ;-). I'm so annoyed at the lack of global scaling on OSx. Well not really, but would be nice if it were easy to change font sizes globally
As for the OPs question, I would try manually playing with "Change only the text size" options on the same place as the DPI configuration is. I do this on my work PC to make annoyingly small fonts larger without making the rest of the GUI blurry or gigantic.
You use to be able to switch by to XP style DPI scaling, but this evidently is no longer possible: http://superuser.com...-in-windows-8-1.