I just upgraded form windows 8.1 to 10, and installed the latest catalyst drivers. My system has an R9 270 that ran 4k resolution (4096 X 2160) perfectly in Windows 8. In windows 10 it stretches, or at least shows the image off the screen a fraction so you can't see sys-tray items etc. So the display shows a small percentage off screen to the left.
If I use the catalyst control centre option of "enable GPU upscaling" it changes the resolution to 1900 X 1080, but the display is fitted to the screen correctly on the tv. If I enable "Virtual Super Resolution" it only adds the resolution 2048 x 1536... not the 4k resolution I am used to running in windows 8.1.
I've played extensively with the custom scaling options available in windows (which are no longer available in the new catalyst centre?)...
How do I get 4k running neatly with the new catalyst drivers?