As far as I know, issues with lack of v-sync in windowed mode are leftovers of the past, WinXP times and old d3d. With latest version of d3d9/d3d11 under win7 it is possible to have v-sync in windowed applications. I don't recall where did I read about it, though.
Perhaps the screen-tearing is caused by something else?
He didn't say anything about tearing, though.
