I enabled AMD SAM about 6 months ago, and the whole I found it increased performance on many of my games, so not something I want to disable. 

However, in the leadup to Sniper 5 coming out I redid Sniper 4 and found it was stuttering every 2 or 3 seconds, despite 140ish FPS. After many changes of settings I discovered it was AMD SAM, with it off was back to silky smooth gameplay, until the next time I played it. Then I found it was stuttering again, so I checked SAM, still off, so I enabled it, and voila, silky smooth again. Lather rinse repeat, basically each consecutive time I play I have to change the setting. 

I then discovered the same thing with Wreckfest, then to my disapointment, Sniper Elite 5, and now Dirt Rally 2.0 as well.

Oddly, doesn't seem to affect and COD Games, Assetto Corsa, RF2, Quantum Leap, Tomb Raider, Spec Ops The Line. 

I can't think of what else to try, save for disabling the feature entirely. I don't think it is related to the driver issue that AMD supposedly fixed in May either, or BIOS (which I've updated), I would expect it to either run or not, alternating whether the game likes SAM one day and not the next is peculiar, hoping someone else might have experienced this and have an idea for a fix.

Cheers