FIXED - My solution was to right click and go to the properties of individual affected apps and tick "disable scaling on higher resolution displays" or something similar. Hope this works for you guys as a temporary fix.
IT WORKS!
Fonts are still not perfect (on win7 they are much crispier), but much better than before!
I had that problem on a surface PRO both with the "onboard" display and the external one:
That worked perfectly! Thanks!
Just to be more precise (for future readers)
1 - Open the folder containing the program
2 - Right click on the executable file
3 - Click Compatibility tab
4a - For single user: check "Disable display scaling on high DPI settings"
4b - For all the users: Click on "Change settings for all users (requires Admin), check the "Disable display scaling on high DPI settings"
I had a big problem reading text (in spotify and PSPAD) on a ~20 inches 1680 x 1050 monitor.
That trick fixed the issue.
Again, Thank you!