I did a test on a G-sync monitor by recording the screen at high speed while moving the cursor around. I can conclude that in my case, G-sync right below the refresh rate has a 3D application that uses the Windows cursor update both on the same frame. The very first monitor refresh with the cursor in a new position caused by pushing the mouse also contains the updated game frame. As soon as the frame rate reaches the refresh rate, V-sync engages, and now the cursor can be seen updating four times without the game showing any signs of mouse input. It's only on the fifth update that it finally responds.Chief Blur Buster wrote:NOTE: Some useful low-lag VSYNC ON code programming techniques is in Page 3 of this thread.
So with 60Hz, that's at least 66ms of extra input lag, but why? One would think that it would add 16.7ms at most, assuming that it simply needs to wait for the next refresh rather than switching the buffers right away.