A few things to try,
1) connect with a different type of cable, i.e. displayport or hdmi or dvi
2) your monitor is defective, replace it.
3) Wait for a fix/try older driver like Matt is eluding to.
Hi Matt and Hardwood and thanks for your replies.
Yesterday the clicking noises started with the game Killing Floor 2. So I sent the monitor back to the vendor for a refund as it must have been faulty. The issue always arose when using frequencies higher than 60Hz.
So now I am looking for a decent FreeSync-enabled monitor. I love that technology and think it's a great step forward, besides Virtual Super Resolution which I also like a lot.
AMD, you just go on developing great hardware and drivers, okay!?