I have RX 460 2gb and driver Adrenalin 18.2.2. When I turn on VSR and GPU scaling I should be able to play 16:9 resolutions such as 1920x1080 on my 16:10 monitor with 1680x1050 native resolution. I know this for a fact because I have R7 260x 1gb card and that worked just fine until I swapped it for RX 460.
Now VSR works smoothly only on 16:10 aspect ratio resolutions while on 16:9 i get 30 fps slowdown/lock.
Another issue is that when changing to 16:9 resolution in full screen games GPU scaling isn't preserving aspect ratio but stretching it to full screen. In desktop it works fine, but as I said previously everything is slowed down to like 30 fps, moving windows is visibly slower and so are games.
If everything worked fine on R7 260x 1gb then it's clearly some bug / artificial limitation causing these issues for RX 460 2gb.