Well, forced vsync works in a lot of games, including DX11 games like BF:BC2, I don't know why it's not working for Gears of War.

And no, the approach to force vsync in D3D games is similar to what D3DOverrider does, the driver vsync doesn't work on Windows Vista/W7

I'll try to find my Gears of War DVD and install it to see if I can reproduce the problem here.