How much does Vertical Sync affect performance?

Question

Video cards

Recently, the question arose of how Vert.Synch. affects FPS in games. For example: A difficult moment in Battlefield 1, there are two explosions nearby, 7 allies, one tank, everyone is shooting, a house is collapsing, a bomb is flying from above, in general, very serious loads on iron. If I have Vert.Sync turned on at this moment, can the FPS sag ???? What if it's disabled?
This question arose due to the fact that, as I think, the card does not have a power reserve and simply does not have time to respond to this, due to frame limitations. And advise what in general about this synchronization, to include or not?
GTX 1060 6GB

Answer 1

Synchronization greatly affects FPS because it limits it from the other side - from above, making it equal to the monitor's refresh rate, that is, it simply does not allow it to rise above its frequency :D.
While it can affect game performance (and sometimes noticeably), it only (though not always) only if the game's frame rate (FPS) is already below the monitor's frame rate.

Answer 2

Strongly.
To find a concrete answer, compare FPS with and without it.
For each individual case, there will be a different result, but you will see the overall impact.
I usually just turn it off in games, I turn the rest of the settings to the maximum.
I'd rather see horizontal stripes in videos than low FPS.