How is windows desktop able to do vsync without input lag?

Joined
Jun 19, 2005
Messages
2,069
Windows desktop does vsync without any input lag when moving the cursor around. Yet once you run a full screen game with vsync on it's a total lag fest. Why is that?
 

kalston

[H]ard|Gawd
Joined
Mar 10, 2011
Messages
1,335
Uh, what? WIndows v-sync does have input lag. I notice a huge difference between Aero enabled and disabled because of this.
 

flod

Gawd
Joined
Jul 10, 2014
Messages
948
the cursor is drawn independently from the rest of the desktop. it has 0 input lag at the top of the screen where a scanout starts. its behavior doesnt change whether you turn aero on or off

but it's pretty easy to see the vsync related lag on the windows desktop... just drag an icon around and notice how it lags behind the windows cursor.

if you're wondering how when you drag a winfow around, the window doesnt lag behind the cursor, i believe it's because the nonlaggy cursor dissappears and a new cursor becomes rendered with the rest of the desktop.
 
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