It's the first ever time something like this happen, i just installed the 14.6 beta drivers and it improved watch dogs performance alot however this happened in football manager.
Did you overclocked your gpu?
The 14.6 drivers are still beta though so it can be expected to have bugs. Just keep an eye on it. If it still artifacts like crazy, then remove and install the lastest stable drivers
I think its how the game is coded. There isn't a Vsync option in game so your fps is probably 1000+fps which is why you can see tearing.
Goto AMD CCC gaming and there are 3D profile you can set to control fps. Look for Frame Rate Control. You can make a specific profile for football manager. Turn "wait for vertical frame rate" on.