I have a rx 590 and in full screen (with vsync ON) my gpu clock downs to 800 mhz instead of 1545 mhz and the gpu memory clock downs to 1000 mhz instead 2000 mhzbut, whitout Vsync, I got in gpu clock 1545 mhz and in gpu memory clock I got 2000 and after a few seconds drops to 1000 and and goes up to 2000 again
photo: https://i.imgur.com/g6y2PoI.jpg
(the first screenshot for some reason I cant take it, so I used a camera)
Im using 19.9.2 drivers
Only happens in a very few games