After upgrading to Windows 10 it's really a pain to use 2D applications, because the window content of all applications is not correctly updated as further described in this post:
Windows 10 issue - Screen is not redrawn properly - Possibly an issue - Microsoft Community
It is a bit application dependent how extreme this issue shows, Chrome for example is absolutely unusable. If you start typing in the url edit field you still see the first character, but all following up ones have a delay of multiple seconds. (the system does not lag of freeze, it simply does not repaint/refresh the view content) If you provoke a refresh, for example by resizing the window, the content is correctly refreshed.
I have an identical system where the only difference is the GPU, nVidia in this case, which works perfectly fine.
As someone else in the Microsoft forums described exactly the behavior which I experience, it is very likely a driver issue and I hope it will be fixed very soon.
Driver version: 15.20.1062.1002-150715a-187327C
Graphics hardware: R9 270