There is certainly an option that you could try... Using the Adrenaline software, which is usually installed with your drivers (latest version with the new UI):
- go to the "Gaming" tab
- you should be on the "Games" tab already
- click on a game
- scroll down on the left where you see the "Graphics" column
- click "Advanced" to see more options
- change "Anti-Aliasing" to your preference
- see also the method and morphological settings that abut it
I haven't verified whether these technologies work. Good luck.