"He experimented problem with Aero, but maybe all its problems were because Aero lost the V-Sync.
When Aero "loses" the V-Sync, in fact, it's not like if it disabled V-Sync, it's just that you have stuttering in every applications: you can perceive it when playing video, or when you use an application with smooth effects (OSD effects, smooth scrolling if you have extension, etc.) or when you move a window.
Aero is good for tearing, but bad for smoothness...
How does Aero lose V-Sync ? Some games, some applications, etc. That's not often, but to avoid it, you have to find what is the trigger...
To find real V-Sync, you have to disable and enable it again (for example with an application which disables desktop composition temporarily).
I've also found that simply reinitializing either display (by switching refresh rates, for instance) also 'reboots' Aero and gets everything properly synced again."
#38057