VESA Adds Adaptive-Sync To DisplayPort 1.2a Specification

[Zan Lynx]

It always annoys me when people say "performance penalty of v-sync". Seriously, its like 47 vs 47 or 32 vs 30. It isn't that big of a performance penalty.

It's also a latency penalty. Not only that but random latency that causes jitter. When the frame rate drops below the sync rate it starts getting delayed from 0 to 16 ms. It's worst when the system is dropping just below 60 Hz. That's why some games intentionally decide they're only going to do 30 fps even if they can sometimes do 60. A solid 30 is better than a random 60.

What you might be seeing is if you have Adaptive V-Sync turned on (it may even be the default on Nvidia these days). I think AMD calls it something else. But that uses V-Sync above 60 and turns it off below 60. That results in a smooth 49 or 42 FPS except it still has nasty visible tearing when you rotate the view.